diff --git a/repos/gems/include/gems/animated_geometry.h b/repos/gems/include/gems/animated_geometry.h
index 346ef9e00c..8d9af66c57 100644
--- a/repos/gems/include/gems/animated_geometry.h
+++ b/repos/gems/include/gems/animated_geometry.h
@@ -60,8 +60,8 @@ class Genode::Animated_rect : private Animator::Item, Noncopyable
 				}
 			}
 
-			int x() const { return _x >> 10; }
-			int y() const { return _y >> 10; }
+			int x() const { return (int)(_x >> 10); }
+			int y() const { return (int)(_y >> 10); }
 		};
 
 		Animated_point _p1 { }, _p2 { };
diff --git a/repos/gems/include/gems/color_hsv.h b/repos/gems/include/gems/color_hsv.h
index a49ec5db49..aab713cd18 100644
--- a/repos/gems/include/gems/color_hsv.h
+++ b/repos/gems/include/gems/color_hsv.h
@@ -21,16 +21,17 @@
  */
 static inline Genode::Color color_from_hsv(unsigned h, unsigned s, unsigned v)
 {
-	typedef Genode::Color Color;
+	using Color   = Genode::Color;
+	using uint8_t = Genode::uint8_t;
 
 	if (s == 0)
 		return Color(v, v, v);
 
-	unsigned char const region = h / 43;
-	unsigned char const remainder = (h - (region*43)) * 6;
-	unsigned char const p = (v*(255 - s)) >> 8,
-	                    q = (v*(255 - ((s*remainder) >> 8))) >> 8,
-	                    t = (v*(255 - ((s*(255 - remainder)) >> 8))) >> 8;
+	uint8_t const region    = (uint8_t)(h / 43);
+	uint8_t const remainder = (uint8_t)((h - (region*43)) * 6);
+	uint8_t const p = (uint8_t)((v*(255 - s)) >> 8),
+	              q = (uint8_t)((v*(255 - ((s*remainder) >> 8))) >> 8),
+	              t = (uint8_t)((v*(255 - ((s*(255 - remainder)) >> 8))) >> 8);
 
 	switch (region) {
 	case 0:  return Color(v, t, p);
diff --git a/repos/gems/include/gems/gui_buffer.h b/repos/gems/include/gems/gui_buffer.h
index 283a0467f7..716a951e6c 100644
--- a/repos/gems/include/gems/gui_buffer.h
+++ b/repos/gems/include/gems/gui_buffer.h
@@ -39,6 +39,8 @@ struct Gui_buffer
 
 	typedef Genode::Attached_ram_dataspace Ram_ds;
 
+	using size_t = Genode::size_t;
+
 	Genode::Ram_allocator &ram;
 	Genode::Region_map    &rm;
 
@@ -116,7 +118,7 @@ struct Gui_buffer
 
 		Pixel_rgb888 const gray(127, 127, 127, 255);
 
-		for (unsigned n = num_pixels; n; n--)
+		for (size_t n = num_pixels; n; n--)
 			*dst++ = gray;
 	}
 
@@ -134,7 +136,7 @@ struct Gui_buffer
 
 	void _update_input_mask()
 	{
-		unsigned const num_pixels = size().count();
+		size_t const num_pixels = size().count();
 
 		unsigned char * const alpha_base = fb_ds.local_addr<unsigned char>()
 		                                 + mode.bytes_per_pixel()*num_pixels;
diff --git a/repos/gems/include/gems/lru_cache.h b/repos/gems/include/gems/lru_cache.h
index 3d92d0784c..6f27a752ec 100644
--- a/repos/gems/include/gems/lru_cache.h
+++ b/repos/gems/include/gems/lru_cache.h
@@ -40,11 +40,11 @@ class Genode::Lru_cache : Noncopyable
 
 		struct Time { unsigned value; };
 
-		Allocator     &_alloc;
-		unsigned const _max_elements;
-		unsigned       _used_elements = 0;
-		Time           _now { 0 };
-		Stats          _stats { };
+		Allocator   &_alloc;
+		size_t  const _max_elements;
+		size_t        _used_elements = 0;
+		Time          _now { 0 };
+		Stats         _stats { };
 
 		class Tag
 		{
diff --git a/repos/gems/include/gems/png_image.h b/repos/gems/include/gems/png_image.h
index 6112ab1c6c..9f93fc0997 100644
--- a/repos/gems/include/gems/png_image.h
+++ b/repos/gems/include/gems/png_image.h
@@ -18,7 +18,10 @@
 #include <os/texture.h>
 
 /* libpng include */
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wconversion"
 #include <png.h>
+#pragma GCC diagnostic pop  /* restore -Wconversion warnings */
 
 /* gems includes */
 #include <gems/chunky_texture.h>
@@ -65,7 +68,7 @@ class Png_image
 				png_bytep const data;
 
 				/* read position, maintained by 'read_callback' */
-				unsigned pos = 0;
+				unsigned long pos = 0;
 
 				static void callback(png_structp png_ptr, png_bytep dst, png_size_t len)
 				{
diff --git a/repos/gems/include/gems/texture_utils.h b/repos/gems/include/gems/texture_utils.h
index edd7d7313d..39f566a769 100644
--- a/repos/gems/include/gems/texture_utils.h
+++ b/repos/gems/include/gems/texture_utils.h
@@ -45,10 +45,10 @@ static void scale(Genode::Texture<PT> const &src, Genode::Texture<PT> &dst,
 			PT            const pixel = pixel_line[pixel_offset];
 			unsigned char const alpha = alpha_line[pixel_offset];
 
-			*d++ = pixel.r();
-			*d++ = pixel.g();
-			*d++ = pixel.b();
-			*d++ = alpha;
+			*d++ = (unsigned char)pixel.r();
+			*d++ = (unsigned char)pixel.g();
+			*d++ = (unsigned char)pixel.b();
+			*d++ = (unsigned char)alpha;
 		}
 
 		dst.rgba(row, dst.size().w(), y);
@@ -83,10 +83,10 @@ static void convert_pixel_format(Genode::Texture<SRC_PT> const &src,
 		unsigned char *d = row;
 		for (unsigned x = 0; x < w; x++, src_pixel++, src_alpha++) {
 
-			*d++ = src_pixel->r();
-			*d++ = src_pixel->g();
-			*d++ = src_pixel->b();
-			*d++ = (*src_alpha * alpha) >> 8;
+			*d++ = (unsigned char)src_pixel->r();
+			*d++ = (unsigned char)src_pixel->g();
+			*d++ = (unsigned char)src_pixel->b();
+			*d++ = (unsigned char)((*src_alpha * alpha) >> 8);
 		}
 
 		/* assign row to destination texture */
diff --git a/repos/gems/include/gems/vfs_font.h b/repos/gems/include/gems/vfs_font.h
index d2c4716759..ccbac1acb7 100644
--- a/repos/gems/include/gems/vfs_font.h
+++ b/repos/gems/include/gems/vfs_font.h
@@ -43,7 +43,7 @@ class Genode::Vfs_font : public Text_painter::Font
 
 				float _advance() const
 				{
-					float value = 256.0*_advance_decimal + _advance_fractional;
+					float value = 256.0f*_advance_decimal + _advance_fractional;
 					return value/256;
 				}
 
@@ -83,7 +83,7 @@ class Genode::Vfs_font : public Text_painter::Font
 		{
 			Allocator &_alloc;
 
-			unsigned const num_bytes;
+			size_t const num_bytes;
 
 			Glyph_header &header;
 
diff --git a/repos/gems/include/polygon_gfx/interpolate_rgba.h b/repos/gems/include/polygon_gfx/interpolate_rgba.h
index eeb127f0f1..82d2c7589e 100644
--- a/repos/gems/include/polygon_gfx/interpolate_rgba.h
+++ b/repos/gems/include/polygon_gfx/interpolate_rgba.h
@@ -57,7 +57,7 @@ static inline void Polygon::interpolate_rgba(Polygon::Color start,
 
 		/* combine current color value with existing pixel via alpha blending */
 		*dst        = PT::mix(*dst, PT(r>>16, g>>16, b>>16), a>>16);
-		*dst_alpha += ((255 - *dst_alpha)*a) >> (16 + 8);
+		*dst_alpha += (unsigned char)(((255 - *dst_alpha)*a) >> (16 + 8));
 
 		/* increment color-component values by ascent */
 		r += r_ascent;
diff --git a/repos/gems/include/polygon_gfx/line_painter.h b/repos/gems/include/polygon_gfx/line_painter.h
index a858633488..65df7f621a 100644
--- a/repos/gems/include/polygon_gfx/line_painter.h
+++ b/repos/gems/include/polygon_gfx/line_painter.h
@@ -43,8 +43,8 @@ struct Line_painter
 			static Fixpoint from_int(long v) { return Fixpoint(v << FRAC_BITS); }
 			static Fixpoint from_raw(long v) { return Fixpoint(v); }
 
-			long integer()    const { return value >> FRAC_BITS; }
-			long fractional() const { return value &  FRAC_MASK; }
+			int integer()    const { return (int)(value >> FRAC_BITS); }
+			int fractional() const { return (int)(value &  FRAC_MASK); }
 	};
 
 	/**
@@ -58,7 +58,7 @@ struct Line_painter
 		{
 			auto fill_segment = [&] (long x1, long y1, long x2, long)
 			{
-				for (long i = x1; i < x2; i++) value[i] = y1;
+				for (long i = x1; i < x2; i++) value[i] = (unsigned char)y1;
 			};
 
 			int const v = 210;
diff --git a/repos/gems/include/polygon_gfx/texturize_rgba.h b/repos/gems/include/polygon_gfx/texturize_rgba.h
index 9aa9a7bf82..e1e9a7a671 100644
--- a/repos/gems/include/polygon_gfx/texturize_rgba.h
+++ b/repos/gems/include/polygon_gfx/texturize_rgba.h
@@ -58,7 +58,7 @@ static inline void Polygon::texturize_rgba(Genode::Point<> start, Genode::Point<
 		int const a = alpha_base[src_offset];
 
 		*dst        = texture_base[src_offset];
-		*dst_alpha += ((255 - *dst_alpha)*a) >> 8;
+		*dst_alpha += (unsigned char)(((255 - *dst_alpha)*a) >> 8);
 
 		/* walk through texture */
 		tx += tx_ascent;
diff --git a/repos/gems/lib/mk/spec/x86_64/vfs_cbe_crypto_memcopy.mk b/repos/gems/lib/mk/spec/x86_64/vfs_cbe_crypto_memcopy.mk
index 7532b0449f..0427316618 100644
--- a/repos/gems/lib/mk/spec/x86_64/vfs_cbe_crypto_memcopy.mk
+++ b/repos/gems/lib/mk/spec/x86_64/vfs_cbe_crypto_memcopy.mk
@@ -5,3 +5,5 @@ vpath vfs.cc $(REP_DIR)/src/lib/vfs/cbe_crypto/
 vpath %.cc   $(REP_DIR)/src/lib/vfs/cbe_crypto/memcopy
 
 SHARED_LIB = yes
+
+CC_CXX_WARN_STRICT_CONVERSION =
diff --git a/repos/gems/src/app/backdrop/main.cc b/repos/gems/src/app/backdrop/main.cc
index 126f2b8b1f..42b34e2675 100644
--- a/repos/gems/src/app/backdrop/main.cc
+++ b/repos/gems/src/app/backdrop/main.cc
@@ -101,8 +101,11 @@ struct Backdrop::Main
 		void flush_surface()
 		{
 			/* blit back to front buffer */
-			blit(surface_ds.local_addr<void>(), surface_num_bytes(),
-			     fb_ds.local_addr<void>(), surface_num_bytes(), surface_num_bytes(), 1);
+			blit(surface_ds.local_addr<void>(),
+			     (unsigned)surface_num_bytes(),
+			     fb_ds.local_addr<void>(),
+			     (unsigned)surface_num_bytes(),
+			     (unsigned)surface_num_bytes(), 1);
 		}
 	};
 
diff --git a/repos/gems/src/app/cbe_tester/target.mk b/repos/gems/src/app/cbe_tester/target.mk
index 6c1dffe287..8f557e2fd0 100644
--- a/repos/gems/src/app/cbe_tester/target.mk
+++ b/repos/gems/src/app/cbe_tester/target.mk
@@ -8,3 +8,5 @@ SRC_CC  += vfs_utilities.cc
 
 INC_DIR := $(PRG_DIR)
 LIBS    += base cbe_cxx cbe_init_cxx cbe_check_cxx cbe_dump_cxx vfs
+
+CC_CXX_WARN_STRICT_CONVERSION =
diff --git a/repos/gems/src/app/cpu_load_display/target.mk b/repos/gems/src/app/cpu_load_display/target.mk
index 31797990e1..0746828d3c 100644
--- a/repos/gems/src/app/cpu_load_display/target.mk
+++ b/repos/gems/src/app/cpu_load_display/target.mk
@@ -2,3 +2,5 @@ TARGET   = cpu_load_display
 SRC_CC   = main.cc
 LIBS     = base
 INC_DIR += $(PRG_DIR)
+
+CC_CXX_WARN_STRICT_CONVERSION =
diff --git a/repos/gems/src/app/decorator/config.h b/repos/gems/src/app/decorator/config.h
index f6412302c8..3b0a6da96f 100644
--- a/repos/gems/src/app/decorator/config.h
+++ b/repos/gems/src/app/decorator/config.h
@@ -156,7 +156,7 @@ class Decorator::Config
 			 * We always report at least one window control. Even if none
 			 * was configured, we present a title.
 			 */
-			return Genode::max(_num_window_controls, 1UL);
+			return Genode::max(_num_window_controls, 1U);
 		}
 
 		/**
@@ -178,11 +178,11 @@ class Decorator::Config
 		/**
 		 * Return gradient intensity in percent
 		 */
-		int gradient_percent(Window_title const &title) const
+		unsigned gradient_percent(Window_title const &title) const
 		{
-			unsigned long result =
-				_buffered_config->xml().attribute_value("gradient", 32UL);
-			
+			unsigned result =
+				_buffered_config->xml().attribute_value("gradient", 32U);
+
 			try {
 				Genode::Session_policy policy(title, _buffered_config->xml());
 				result = policy.attribute_value("gradient", result);
diff --git a/repos/gems/src/app/decorator/main.cc b/repos/gems/src/app/decorator/main.cc
index bcb9c1ed76..4440d51551 100644
--- a/repos/gems/src/app/decorator/main.cc
+++ b/repos/gems/src/app/decorator/main.cc
@@ -185,7 +185,7 @@ struct Decorator::Main : Window_factory_base
 		for (;;) {
 			try {
 				return new (_heap)
-					Window(window_node.attribute_value("id", 0UL),
+					Window(window_node.attribute_value("id", 0U),
 					       _gui, _animator, _decorator_config);
 			}
 			catch (Genode::Out_of_ram) {
diff --git a/repos/gems/src/app/depot_download_manager/main.cc b/repos/gems/src/app/depot_download_manager/main.cc
index a3adc27bef..2b29f57d0d 100644
--- a/repos/gems/src/app/depot_download_manager/main.cc
+++ b/repos/gems/src/app/depot_download_manager/main.cc
@@ -43,7 +43,7 @@ struct Depot_download_manager::Child_exit_state
 				exists = true;
 				if (child.has_attribute("exited")) {
 					exited = true;
-					code = child.attribute_value("exited", 0L);
+					code = (int)child.attribute_value("exited", 0L);
 				}
 			}
 		});
diff --git a/repos/gems/src/app/driver_manager/main.cc b/repos/gems/src/app/driver_manager/main.cc
index 72c7ae63b2..577ba95b38 100644
--- a/repos/gems/src/app/driver_manager/main.cc
+++ b/repos/gems/src/app/driver_manager/main.cc
@@ -466,8 +466,8 @@ void Driver_manager::Main::_handle_pci_devices_update()
 
 	_pci_devices.xml().for_each_sub_node([&] (Xml_node device) {
 
-		uint16_t const vendor_id  = device.attribute_value("vendor_id",  0UL);
-		uint16_t const class_code = device.attribute_value("class_code", 0UL) >> 8;
+		uint16_t const vendor_id  = (uint16_t)device.attribute_value("vendor_id",  0U);
+		uint16_t const class_code = (uint16_t)(device.attribute_value("class_code", 0U) >> 8);
 
 		enum {
 			VENDOR_VBOX  = 0x80EEU,
diff --git a/repos/gems/src/app/file_vault/child_exit_state.h b/repos/gems/src/app/file_vault/child_exit_state.h
index 6ab3af6b76..3e6b5c9e45 100644
--- a/repos/gems/src/app/file_vault/child_exit_state.h
+++ b/repos/gems/src/app/file_vault/child_exit_state.h
@@ -52,7 +52,7 @@ class File_vault::Child_exit_state
 
 					if (child.has_attribute("exited")) {
 						_exited = true;
-						_code = child.attribute_value("exited", 0L);
+						_code = (int)child.attribute_value("exited", 0L);
 					}
 
 					_responsive = (child.attribute_value("skipped_heartbeats", 0U) <= 2);
diff --git a/repos/gems/src/app/file_vault/sync_to_cbe_vfs_init/main.cc b/repos/gems/src/app/file_vault/sync_to_cbe_vfs_init/main.cc
index 087b0291f3..a0e6a001e1 100644
--- a/repos/gems/src/app/file_vault/sync_to_cbe_vfs_init/main.cc
+++ b/repos/gems/src/app/file_vault/sync_to_cbe_vfs_init/main.cc
@@ -13,10 +13,13 @@
 
 /* libC includes */
 extern "C" {
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wconversion"
 #include <fcntl.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <unistd.h>
+#pragma GCC diagnostic pop  /* restore -Wconversion warnings */
 }
 
 int main(int, char **)
diff --git a/repos/gems/src/app/gpt_write/target.mk b/repos/gems/src/app/gpt_write/target.mk
index 21e6aa13df..2459ac23a7 100644
--- a/repos/gems/src/app/gpt_write/target.mk
+++ b/repos/gems/src/app/gpt_write/target.mk
@@ -2,3 +2,5 @@ TARGET  := gpt_write
 LIBS    := base jitterentropy
 SRC_CC  := main.cc util.cc
 INC_DIR := $(PRG_DIR)
+
+CC_CXX_WARN_STRICT_CONVERSION =
diff --git a/repos/gems/src/app/menu_view/depgraph_widget.h b/repos/gems/src/app/menu_view/depgraph_widget.h
index da0f3724be..dfdd0bb801 100644
--- a/repos/gems/src/app/menu_view/depgraph_widget.h
+++ b/repos/gems/src/app/menu_view/depgraph_widget.h
@@ -673,7 +673,7 @@ struct Menu_view::Depgraph_widget : Widget
 		           y4 = p2.y();
 
 		/* subdivide the curve depending on the size of its bounding box */
-		unsigned const levels = max(log2(max(abs(x4 - x1), abs(y4 - y1)) >> 2), 3);
+		unsigned const levels = (unsigned)max(log2(max(abs(x4 - x1), abs(y4 - y1)) >> 2), 3);
 
 		bezier(x1 << 8, y1 << 8, x2 << 8, y2 << 8,
 		       x3 << 8, y3 << 8, x4 << 8, y4 << 8, draw_segment, levels);
diff --git a/repos/gems/src/app/menu_view/main.cc b/repos/gems/src/app/menu_view/main.cc
index 24e0a2d80e..77fbf497f8 100644
--- a/repos/gems/src/app/menu_view/main.cc
+++ b/repos/gems/src/app/menu_view/main.cc
@@ -231,8 +231,8 @@ void Menu_view::Main::_handle_dialog_update()
 
 		_position = Decorator::point_attribute(config);
 
-		_configured_size = Area(config.attribute_value("width",  0UL),
-		                        config.attribute_value("height", 0UL));
+		_configured_size = Area(config.attribute_value("width",  0U),
+		                        config.attribute_value("height", 0U));
 	} catch (...) { }
 
 	_dialog_rom.update();
diff --git a/repos/gems/src/app/menu_view/scratch_surface.h b/repos/gems/src/app/menu_view/scratch_surface.h
index 9e1a436e5d..76ad1941b7 100644
--- a/repos/gems/src/app/menu_view/scratch_surface.h
+++ b/repos/gems/src/app/menu_view/scratch_surface.h
@@ -40,7 +40,7 @@ struct Menu_view::Additive_alpha
 	template <typename TPT, typename PT>
 	static void transfer(TPT const &, int src_a, int alpha, PT &dst)
 	{
-		dst.pixel += (alpha*src_a) >> 8;
+		dst.pixel += (uint8_t)((alpha*src_a) >> 8);
 	}
 
 	static Surface_base::Pixel_format format() { return Surface_base::UNKNOWN; }
diff --git a/repos/gems/src/app/nano3d/main.cc b/repos/gems/src/app/nano3d/main.cc
index 3ce911e6db..06004e07c4 100644
--- a/repos/gems/src/app/nano3d/main.cc
+++ b/repos/gems/src/app/nano3d/main.cc
@@ -60,7 +60,7 @@ class Scene : public Nano3d::Scene<PT>
 
 						int const radius = Nano3d::sqrt(dx*dx + dy*dy);
 
-						alpha[y][x] = 250 - (radius*250)/r_max;
+						alpha[y][x] = (unsigned char)(250 - (radius*250)/r_max);
 
 						if ((x&4) ^ (y&4))
 							alpha[y][x] = 0;
diff --git a/repos/gems/src/app/sculpt_manager/graph.cc b/repos/gems/src/app/sculpt_manager/graph.cc
index 8d4d1a4423..b9337f5314 100644
--- a/repos/gems/src/app/sculpt_manager/graph.cc
+++ b/repos/gems/src/app/sculpt_manager/graph.cc
@@ -302,12 +302,12 @@ Dialog::Hover_result Graph::hover(Xml_node hover)
 			if (!dialog.has_type("dialog")) return Rect();
 
 			auto point_from_xml = [] (Xml_node node) {
-				return Point(node.attribute_value("xpos", 0L),
-				             node.attribute_value("ypos", 0L)); };
+				return Point((int)node.attribute_value("xpos", 0L),
+				             (int)node.attribute_value("ypos", 0L)); };
 
 			auto area_from_xml = [] (Xml_node node) {
-				return Area(node.attribute_value("width",  0UL),
-				            node.attribute_value("height", 0UL)); };
+				return Area(node.attribute_value("width",  0U),
+				            node.attribute_value("height", 0U)); };
 
 			if (!dialog.has_sub_node("depgraph")) return Rect();
 			Xml_node const depgraph = dialog.sub_node("depgraph");
diff --git a/repos/gems/src/app/sculpt_manager/main.cc b/repos/gems/src/app/sculpt_manager/main.cc
index d4baba6379..e5399a69cb 100644
--- a/repos/gems/src/app/sculpt_manager/main.cc
+++ b/repos/gems/src/app/sculpt_manager/main.cc
@@ -107,7 +107,7 @@ struct Sculpt::Main : Input_event_handler,
 					dir.for_each_sub_node("dir", [&] (Xml_node type) {
 						if (type.attribute_value("name", String<16>()) == "text") {
 							type.for_each_sub_node("ttf", [&] (Xml_node ttf) {
-								float const px = ttf.attribute_value("size_px", 0.0);
+								double const px = ttf.attribute_value("size_px", 0.0);
 								if (px > 0.0)
 									_font_size_px = px; }); } }); } }); });
 
@@ -380,7 +380,7 @@ struct Sculpt::Main : Input_event_handler,
 
 	Settings _settings { };
 
-	float _font_size_px = 14;
+	double _font_size_px = 14;
 
 	Area _screen_size { };
 
@@ -1169,10 +1169,10 @@ void Sculpt::Main::_handle_window_layout()
 
 			Xml_node const floating = node.sub_node("floating");
 
-			top    = floating.attribute_value("top",    0UL);
-			bottom = floating.attribute_value("bottom", 0UL);
-			left   = floating.attribute_value("left",   0UL);
-			right  = floating.attribute_value("right",  0UL);
+			top    = floating.attribute_value("top",    0U);
+			bottom = floating.attribute_value("bottom", 0U);
+			left   = floating.attribute_value("left",   0U);
+			right  = floating.attribute_value("right",  0U);
 		}
 	};
 
@@ -1199,8 +1199,8 @@ void Sculpt::Main::_handle_window_layout()
 	Xml_node const window_list = _window_list.xml();
 
 	auto win_size = [&] (Xml_node win) {
-		return Area(win.attribute_value("width",  0UL),
-		            win.attribute_value("height", 0UL)); };
+		return Area(win.attribute_value("width",  0U),
+		            win.attribute_value("height", 0U)); };
 
 	unsigned panel_height = 0;
 	_with_window(window_list, panel_view_label, [&] (Xml_node win) {
@@ -1393,7 +1393,7 @@ void Sculpt::Main::_handle_gui_mode()
 
 	if (!_settings.manual_fonts_config) {
 
-		_font_size_px = (float)mode.area.h() / 60.0;
+		_font_size_px = (double)mode.area.h() / 60.0;
 
 		/*
 		 * Limit lower bound of font size. Otherwise, the glyph rendering
@@ -1413,7 +1413,7 @@ void Sculpt::Main::_handle_gui_mode()
 				gen_named_node(xml, "dir", "fonts", [&] () {
 
 					auto gen_ttf_dir = [&] (char const *dir_name,
-					                        char const *ttf_path, float size_px) {
+					                        char const *ttf_path, double size_px) {
 
 						gen_named_node(xml, "dir", dir_name, [&] () {
 							gen_named_node(xml, "ttf", "regular", [&] () {
@@ -1450,7 +1450,7 @@ void Sculpt::Main::_handle_gui_mode()
 
 	_screen_size = mode.area;
 	_panel_menu_view.min_width = _screen_size.w();
-	unsigned const menu_width = max(_font_size_px*21, 320.0);
+	unsigned const menu_width = max((unsigned)(_font_size_px*21.0), 320u);
 	_main_menu_view.min_width = menu_width;
 	_network.min_dialog_width(menu_width);
 
diff --git a/repos/gems/src/app/sculpt_manager/model/access_point.h b/repos/gems/src/app/sculpt_manager/model/access_point.h
index 4d32189769..6fde683457 100644
--- a/repos/gems/src/app/sculpt_manager/model/access_point.h
+++ b/repos/gems/src/app/sculpt_manager/model/access_point.h
@@ -71,7 +71,7 @@ struct Sculpt::Access_point_update_policy : List_model<Access_point>::Update_pol
 
 	void update_element(Access_point &ap, Xml_node node)
 	{
-		ap.quality = node.attribute_value("quality", 0UL);
+		ap.quality = node.attribute_value("quality", 0U);
 	}
 
 	static bool element_matches_xml_node(Access_point const &elem, Xml_node node)
diff --git a/repos/gems/src/app/sculpt_manager/model/child_exit_state.h b/repos/gems/src/app/sculpt_manager/model/child_exit_state.h
index c176bc284f..b5989c2d5d 100644
--- a/repos/gems/src/app/sculpt_manager/model/child_exit_state.h
+++ b/repos/gems/src/app/sculpt_manager/model/child_exit_state.h
@@ -43,7 +43,7 @@ struct Sculpt::Child_exit_state
 
 				if (child.has_attribute("exited")) {
 					exited = true;
-					code = child.attribute_value("exited", 0L);
+					code = (int)child.attribute_value("exited", 0L);
 				}
 
 				responsive = (child.attribute_value("skipped_heartbeats", 0U) <= 2);
diff --git a/repos/gems/src/app/sculpt_manager/model/partition.h b/repos/gems/src/app/sculpt_manager/model/partition.h
index 9a0657e813..34397d7577 100644
--- a/repos/gems/src/app/sculpt_manager/model/partition.h
+++ b/repos/gems/src/app/sculpt_manager/model/partition.h
@@ -108,7 +108,7 @@ struct Sculpt::Partition : List_model<Partition>::Element
 			Number const number = node.attribute_value("number", Number());
 
 			unsigned long const block_size =
-				node.attribute_value("block_size", 512ULL);
+				node.attribute_value("block_size", 512UL);
 
 			unsigned long long const expandable =
 				node.attribute_value("expandable", 0ULL);
diff --git a/repos/gems/src/app/sculpt_manager/runtime.h b/repos/gems/src/app/sculpt_manager/runtime.h
index 3b3efc5932..e61cc092d1 100644
--- a/repos/gems/src/app/sculpt_manager/runtime.h
+++ b/repos/gems/src/app/sculpt_manager/runtime.h
@@ -51,7 +51,7 @@ namespace Sculpt {
 	void gen_launcher_query_start_content(Xml_generator &);
 
 	void gen_runtime_view_start_content(Xml_generator &, Child_state const &,
-	                                    float font_size);
+	                                    double font_size);
 
 	struct Inspect_view_version { unsigned value; };
 	void gen_inspect_view(Xml_generator &, Storage_devices const &,
diff --git a/repos/gems/src/app/sculpt_manager/runtime/runtime_view.cc b/repos/gems/src/app/sculpt_manager/runtime/runtime_view.cc
index fc3289c909..8e48b9b4b0 100644
--- a/repos/gems/src/app/sculpt_manager/runtime/runtime_view.cc
+++ b/repos/gems/src/app/sculpt_manager/runtime/runtime_view.cc
@@ -20,7 +20,7 @@
 
 void Sculpt::gen_runtime_view_start_content(Xml_generator &xml,
                                             Child_state const &state,
-                                            float font_size)
+                                            double font_size)
 {
 	state.gen_start_node_content(xml);
 
diff --git a/repos/gems/src/app/sculpt_manager/view/download_status.h b/repos/gems/src/app/sculpt_manager/view/download_status.h
index 267a3b3189..57d3c8d7b3 100644
--- a/repos/gems/src/app/sculpt_manager/view/download_status.h
+++ b/repos/gems/src/app/sculpt_manager/view/download_status.h
@@ -42,9 +42,9 @@ void Sculpt::gen_download_status(Xml_generator &xml, Xml_node state)
 
 					typedef String<16> Info;
 
-					Info        info  = archive.attribute_value("state", Info());
-					float const total = archive.attribute_value("total", 0.0);
-					float const now   = archive.attribute_value("now",   0.0);
+					Info         info  = archive.attribute_value("state", Info());
+					double const total = archive.attribute_value("total", 0.0d);
+					double const now   = archive.attribute_value("now",   0.0d);
 
 					if (info == "download") {
 						if (total > 0.0)
diff --git a/repos/gems/src/app/text_area/dynamic_array.h b/repos/gems/src/app/text_area/dynamic_array.h
index 2db0574db7..04ced3ba4b 100644
--- a/repos/gems/src/app/text_area/dynamic_array.h
+++ b/repos/gems/src/app/text_area/dynamic_array.h
@@ -41,7 +41,7 @@ struct Text_area::Dynamic_array
 
 		Element *_array = nullptr;
 
-		unsigned _capacity    = 0;
+		size_t   _capacity    = 0;
 		unsigned _upper_bound = 0; /* index after last used element */
 
 		bool _index_valid(Index at) const
diff --git a/repos/gems/src/app/themed_decorator/main.cc b/repos/gems/src/app/themed_decorator/main.cc
index 1a0346403a..a8d1f05b70 100644
--- a/repos/gems/src/app/themed_decorator/main.cc
+++ b/repos/gems/src/app/themed_decorator/main.cc
@@ -173,7 +173,7 @@ struct Decorator::Main : Window_factory_base
 		for (;;) {
 			try {
 				return new (_heap)
-					Window(_env, window_node.attribute_value("id", 0UL),
+					Window(_env, window_node.attribute_value("id", 0U),
 					       _gui, _animator, _theme, _decorator_config);
 			}
 			catch (Out_of_ram) {
diff --git a/repos/gems/src/app/themed_decorator/theme.cc b/repos/gems/src/app/themed_decorator/theme.cc
index 248bd81846..8b55f595ba 100644
--- a/repos/gems/src/app/themed_decorator/theme.cc
+++ b/repos/gems/src/app/themed_decorator/theme.cc
@@ -124,10 +124,10 @@ struct Margins_from_metadata : Decorator::Theme::Margins
 		Decorator::Theme::Margins()
 	{
 		Genode::Xml_node aura = metadata(alloc).sub_node(sub_node);
-		top    = aura.attribute_value("top",    0UL);
-		bottom = aura.attribute_value("bottom", 0UL);
-		left   = aura.attribute_value("left",   0UL);
-		right  = aura.attribute_value("right",  0UL);
+		top    = aura.attribute_value("top",    0U);
+		bottom = aura.attribute_value("bottom", 0U);
+		left   = aura.attribute_value("left",   0U);
+		right  = aura.attribute_value("right",  0U);
 	}
 };
 
diff --git a/repos/gems/src/app/vfs_replay/component.cc b/repos/gems/src/app/vfs_replay/component.cc
index 91f5889cd9..0eb37e595d 100644
--- a/repos/gems/src/app/vfs_replay/component.cc
+++ b/repos/gems/src/app/vfs_replay/component.cc
@@ -48,7 +48,7 @@ class Vfs_replay
 
 		Xml_node _replay_node;
 		Xml_node _request_node { "<empty/>" };
-		unsigned _num_requests { 0 };
+		size_t   _num_requests { 0 };
 		unsigned _curr_request_id { 0 };
 
 		bool _finished { false };
diff --git a/repos/gems/src/app/window_layouter/assign.h b/repos/gems/src/app/window_layouter/assign.h
index 7d30a047e4..840177db0e 100644
--- a/repos/gems/src/app/window_layouter/assign.h
+++ b/repos/gems/src/app/window_layouter/assign.h
@@ -134,7 +134,7 @@ class Window_layouter::Assign : public List_model<Assign>::Element
 
 			bool suffix_matches = false;
 			if (label.length() >= _label_suffix.length()) {
-				unsigned const offset = label.length() - _label_suffix.length();
+				unsigned const offset = (unsigned)(label.length() - _label_suffix.length());
 				suffix_matches = !strcmp(_label.string() + offset, _label_suffix.string());
 			}
 
diff --git a/repos/gems/src/app/window_layouter/decorator_margins.h b/repos/gems/src/app/window_layouter/decorator_margins.h
index ad21e6b1af..1539b135f9 100644
--- a/repos/gems/src/app/window_layouter/decorator_margins.h
+++ b/repos/gems/src/app/window_layouter/decorator_margins.h
@@ -26,10 +26,10 @@ struct Window_layouter::Decorator_margins
 
 	Decorator_margins(Xml_node node)
 	:
-		top   (node.attribute_value("top",    0UL)),
-		bottom(node.attribute_value("bottom", 0UL)),
-		left  (node.attribute_value("left",   0UL)),
-		right (node.attribute_value("right",  0UL))
+		top   (node.attribute_value("top",    0U)),
+		bottom(node.attribute_value("bottom", 0U)),
+		left  (node.attribute_value("left",   0U)),
+		right (node.attribute_value("right",  0U))
 	{ }
 
 	/**
diff --git a/repos/gems/src/app/window_layouter/main.cc b/repos/gems/src/app/window_layouter/main.cc
index 97168a61c8..c4bf536a07 100644
--- a/repos/gems/src/app/window_layouter/main.cc
+++ b/repos/gems/src/app/window_layouter/main.cc
@@ -594,7 +594,7 @@ void Window_layouter::Main::_handle_hover()
 	try {
 		Xml_node const hover_window_xml = _hover.xml().sub_node("window");
 
-		_user_state.hover(hover_window_xml.attribute_value("id", 0UL),
+		_user_state.hover(hover_window_xml.attribute_value("id", 0U),
 		                  _element_from_hover_model(hover_window_xml));
 	}
 
@@ -632,7 +632,7 @@ void Window_layouter::Main::_handle_focus_request()
 {
 	_focus_request.update();
 
-	int const id = _focus_request.xml().attribute_value("id", 0L);
+	int const id = (int)_focus_request.xml().attribute_value("id", 0L);
 
 	/* don't apply the same focus request twice */
 	if (id == _handled_focus_request_id)
diff --git a/repos/gems/src/app/window_layouter/target.h b/repos/gems/src/app/window_layouter/target.h
index 6ae9b1cb8c..b0f48eeece 100644
--- a/repos/gems/src/app/window_layouter/target.h
+++ b/repos/gems/src/app/window_layouter/target.h
@@ -40,7 +40,7 @@ class Window_layouter::Target : Noncopyable
 		Target(Xml_node target, Rect geometry, Visible visible)
 		:
 			_name (target.attribute_value("name", Name())),
-			_layer(target.attribute_value("layer", 9999UL)),
+			_layer(target.attribute_value("layer", 9999U)),
 			_geometry(geometry),
 			_visible(visible == Visible::YES)
 		{ }
diff --git a/repos/gems/src/app/window_layouter/target_list.h b/repos/gems/src/app/window_layouter/target_list.h
index 5797758641..df44e2f9eb 100644
--- a/repos/gems/src/app/window_layouter/target_list.h
+++ b/repos/gems/src/app/window_layouter/target_list.h
@@ -42,22 +42,22 @@ class Window_layouter::Target_list
 		void _process_rec(Xml_node node, Rect avail, bool row,
 		                  Target::Visible visible)
 		{
-			unsigned long const avail_px = row ? avail.w() : avail.h();
+			unsigned const avail_px = row ? avail.w() : avail.h();
 
 			char const *sub_node_type = row ? "column" : "row";
 			char const *px_size_attr  = row ? "width"  : "height";
 
-			unsigned long px_pos = row ? avail.x1() : avail.y1();
+			unsigned px_pos = row ? avail.x1() : avail.y1();
 
-			unsigned long const default_weight = 1;
+			unsigned const default_weight = 1;
 
 			/*
 			 * Determinine space reserved in pixels, the total weight, and
 			 * number of weighted rows/columns.
 			 */
-			unsigned long preserved_pixels = 0;
-			unsigned long total_weight     = 0;
-			unsigned long num_weighted     = 0;
+			unsigned preserved_pixels = 0;
+			unsigned total_weight     = 0;
+			unsigned num_weighted     = 0;
 
 			/* ignore weight if pixel size is provided */
 			auto weight_attr_value = [&] (Xml_node node) {
@@ -65,7 +65,7 @@ class Window_layouter::Target_list
 				     ? 0 : node.attribute_value("weight", default_weight); };
 
 			node.for_each_sub_node(sub_node_type, [&] (Xml_node child) {
-				preserved_pixels += child.attribute_value(px_size_attr, 0UL);
+				preserved_pixels += child.attribute_value(px_size_attr, 0U);
 				total_weight     += weight_attr_value(child);
 				num_weighted     += child.has_attribute(px_size_attr) ? 0 : 1;
 			});
@@ -76,26 +76,26 @@ class Window_layouter::Target_list
 			}
 
 			/* amount of pixels we can use for weighed columns */
-			unsigned long const weigthed_avail = avail_px - preserved_pixels;
+			unsigned const weigthed_avail = avail_px - preserved_pixels;
 
 			/*
 			 * Calculate positions
 			 */
-			unsigned long count_weighted = 0;
-			unsigned long used_weighted  = 0;
+			unsigned count_weighted = 0;
+			unsigned used_weighted  = 0;
 			node.for_each_sub_node(sub_node_type, [&] (Xml_node child) {
 
 				auto calc_px_size = [&] () {
 
-					unsigned long const px = child.attribute_value(px_size_attr, 0UL);
+					unsigned const px = child.attribute_value(px_size_attr, 0U);
 					if (px)
 						return px;
 
-					unsigned long const weight = weight_attr_value(child);
+					unsigned const weight = weight_attr_value(child);
 					if (weight && total_weight)
 						return (((weight << 16)*weigthed_avail)/total_weight) >> 16;
 
-					return 0UL;
+					return 0U;
 				};
 
 				bool const weighted = !child.has_attribute(px_size_attr);
@@ -107,9 +107,9 @@ class Window_layouter::Target_list
 				bool const last_weighted = weighted
 				                        && (count_weighted == num_weighted);
 
-				unsigned long const px_size = last_weighted
-				                            ? (weigthed_avail - used_weighted)
-				                            : calc_px_size();
+				unsigned const px_size = last_weighted
+				                       ? (weigthed_avail - used_weighted)
+				                       : calc_px_size();
 
 				if (weighted)
 					used_weighted += px_size;
diff --git a/repos/gems/src/app/window_layouter/window_list.h b/repos/gems/src/app/window_layouter/window_list.h
index a6fd89bf83..6945de0cf7 100644
--- a/repos/gems/src/app/window_layouter/window_list.h
+++ b/repos/gems/src/app/window_layouter/window_list.h
@@ -71,8 +71,8 @@ class Window_layouter::Window_list
 
 			Window &create_element(Xml_node node)
 			{
-				unsigned long const id           = node.attribute_value("id", 0UL);
-				Area          const initial_size = area_attribute(node);
+				unsigned const id           = node.attribute_value("id", 0U);
+				Area     const initial_size = area_attribute(node);
 
 				Window::Label const label =
 					node.attribute_value("label",Window::Label());
@@ -94,7 +94,7 @@ class Window_layouter::Window_list
 
 			static bool element_matches_xml_node(Window const &elem, Xml_node node)
 			{
-				return elem.has_id(node.attribute_value("id", 0UL));
+				return elem.has_id(node.attribute_value("id", 0U));
 			}
 		};
 
diff --git a/repos/gems/src/lib/ttf_font/ttf_font.cc b/repos/gems/src/lib/ttf_font/ttf_font.cc
index 17c7a4918e..7f91b735b9 100644
--- a/repos/gems/src/lib/ttf_font/ttf_font.cc
+++ b/repos/gems/src/lib/ttf_font/ttf_font.cc
@@ -26,6 +26,9 @@
  * STB TrueType library
  */
 
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wconversion"
+
 static void *local_malloc(Genode::size_t, void *);
 static void  local_free(void *, void *);
 #define STBTT_malloc local_malloc
@@ -38,6 +41,8 @@ static void  local_free(void *, void *);
 #define STB_TRUETYPE_IMPLEMENTATION
 #include "stb_truetype.h"
 
+#pragma GCC diagnostic pop  /* restore -Wconversion warnings */
+
 static void *STBTT_malloc(size_t size, void *userdata)
 {
 	return ((Genode::Allocator *)userdata)->alloc(size);
@@ -83,7 +88,7 @@ struct Ttf_font::Glyph_buffer
 			{
 				auto fill_segment = [&] (long x1, long y1, long x2, long) {
 					for (long i = x1>>8; i < x2>>8; i++)
-						value[i] = Genode::min(255, y1>>8); };
+						value[i] = (unsigned char)Genode::min(255l, y1>>8); };
 
 				bezier(0, 0, 0, 130<<8, 256<<8, 260<<8, fill_segment, 7);
 				value[0] = 0;
@@ -198,7 +203,7 @@ Ttf_font::Glyph_buffer::render_shifted(Codepoint      const c,
 	return Glyph { .width   = width,
 	               .height  = height,
 	               .vpos    = (unsigned)((int)baseline + y0),
-	               .advance = scale*advance,
+	               .advance = scale * (float)advance,
 	               .values  = _values + _headroom };
 }
 
@@ -214,13 +219,14 @@ static Text_painter::Area obtain_bounding_box(stbtt_fontinfo const &font, float
 	int x0 = 0, y0 = 0, x1 = 0, y1 = 0;
 	stbtt_GetFontBoundingBox(&font, &x0, &y0, &x1, &y1);
 
-	int const w = x1 - x0 + 1,
-	          h = y1 - y0 + 1;
+	float const w = (float)(x1 - x0 + 1),
+	            h = (float)(y1 - y0 + 1);
 
 	if (w < 1 || h < 1)
 		throw Ttf_font::Unsupported_data();
 
-	return Text_painter::Area(w*scale + 2*PAD_X, h*scale + 2*PAD_Y);
+	return Text_painter::Area((unsigned)(w*scale) + 2*PAD_X,
+	                          (unsigned)(h*scale) + 2*PAD_Y);
 }
 
 
@@ -229,7 +235,7 @@ static unsigned obtain_baseline(stbtt_fontinfo const &font, float scale)
 	int ascent = 0;
 	stbtt_GetFontVMetrics(&font, &ascent, 0, 0);
 
-	return (unsigned)(ascent*scale);
+	return (unsigned)((float)ascent*scale);
 }
 
 
@@ -253,7 +259,7 @@ Ttf_font::Ttf_font(Allocator &alloc, void const *ttf, float px)
 	_px(px),
 	_scale(stbtt_ScaleForPixelHeight(&_stbtt_font_info, px)),
 	_baseline(obtain_baseline(_stbtt_font_info, _scale)),
-	_height(px + 0.5 /* round to integer */),
+	_height((unsigned)(px + 0.5)),
 	_bounding_box(obtain_bounding_box(_stbtt_font_info, _scale)),
 	_glyph_buffer(*new (alloc) Glyph_buffer(alloc, _bounding_box))
 { }
@@ -284,7 +290,7 @@ void Ttf_font::_apply_glyph(Codepoint c, Apply_fn const &fn) const
 	float best_shift_y = 0;
 	{
 		unsigned sharpest = 0;
-		for (float shift_y = -0.3; shift_y < 0.3; shift_y += 0.066) {
+		for (float shift_y = -0.3f; shift_y < 0.3f; shift_y += 0.066f) {
 
 			Glyph const glyph =
 				_glyph_buffer.render_shifted(c, _stbtt_font_info, _scale,
@@ -311,7 +317,9 @@ Text_painter::Font::Advance_info Ttf_font::advance_info(Codepoint c) const
 	int advance = 0, lsb = 0;
 	stbtt_GetCodepointHMetrics(&_stbtt_font_info, c.value, &advance, &lsb);
 
-	return Font::Advance_info { .width   = (unsigned)(_scale*advance),
-	                            .advance = _scale*advance };
+	float const scaled_advance = _scale * (float)advance;
+
+	return Font::Advance_info { .width   = (unsigned)scaled_advance,
+	                            .advance = scaled_advance };
 }
 
diff --git a/repos/gems/src/lib/vfs/cbe_crypto/vfs.cc b/repos/gems/src/lib/vfs/cbe_crypto/vfs.cc
index 9251b1ddb9..ba2d41a45a 100644
--- a/repos/gems/src/lib/vfs/cbe_crypto/vfs.cc
+++ b/repos/gems/src/lib/vfs/cbe_crypto/vfs.cc
@@ -529,7 +529,7 @@ class Vfs_cbe_crypto::Keys_file_system : public Vfs::File_system
 				}
 
 				try {
-					Key_file_system const &fs = _key_reg.by_index(index);
+					Key_file_system const &fs = _key_reg.by_index((unsigned)index);
 					Genode::String<32> name { fs.key_id() };
 
 					out = {
diff --git a/repos/gems/src/lib/vfs/cbe_trust_anchor/aes_256.cc b/repos/gems/src/lib/vfs/cbe_trust_anchor/aes_256.cc
index ca24e5e243..31ee54c03a 100644
--- a/repos/gems/src/lib/vfs/cbe_trust_anchor/aes_256.cc
+++ b/repos/gems/src/lib/vfs/cbe_trust_anchor/aes_256.cc
@@ -60,7 +60,7 @@ void Aes_256::encrypt_with_zeroed_iv(unsigned char       *ciphertext_base,
                                      size_t               key_size)
 {
 	Openssl::AES_KEY aes_key;
-	if (AES_set_encrypt_key(key_base, key_size * 8, &aes_key)) {
+	if (AES_set_encrypt_key(key_base, (int)(key_size * 8), &aes_key)) {
 		class Failed_to_set_key { };
 		throw Failed_to_set_key { };
 	}
@@ -82,7 +82,7 @@ void Aes_256::decrypt_with_zeroed_iv(unsigned char       *plaintext_base,
                                      size_t               key_size)
 {
 	Openssl::AES_KEY aes_key;
-	if (AES_set_decrypt_key(key_base, key_size * 8, &aes_key)) {
+	if (AES_set_decrypt_key(key_base, (int)(key_size * 8), &aes_key)) {
 		class Failed_to_set_key { };
 		throw Failed_to_set_key { };
 	}
diff --git a/repos/gems/src/lib/vfs/trace/vfs.cc b/repos/gems/src/lib/vfs/trace/vfs.cc
index 6f96afe5a5..c6b02a6668 100644
--- a/repos/gems/src/lib/vfs/trace/vfs.cc
+++ b/repos/gems/src/lib/vfs/trace/vfs.cc
@@ -128,7 +128,7 @@ class Vfs_trace::Trace_buffer_file_system : public Single_file_system
 				out_count = 0;
 				_entries.for_each_new_entry([&](Trace::Buffer::Entry entry) {
 					file_size size = min(count - out_count, entry.length());
-					memcpy(dst + out_count, entry.data(), size);
+					memcpy(dst + out_count, entry.data(), (size_t)size);
 					out_count += size;
 
 					if (out_count == count)
@@ -351,7 +351,7 @@ struct Vfs_trace::Local_factory : File_system_factory
 	Trace::Connection  _trace;
 	enum { MAX_SUBJECTS = 128 };
 	Trace::Subject_id  _subjects[MAX_SUBJECTS];
-	unsigned           _subject_count { 0 };
+	size_t             _subject_count { 0 };
 	Trace::Policy_id   _policy_id { 0 };
 
 	Directory_tree     _tree { _env.alloc() };
@@ -402,7 +402,7 @@ struct Vfs_trace::Local_factory : File_system_factory
 			}
 		}
 
-		for (unsigned i = 0; i < _subject_count; i++) {
+		for (size_t i = 0; i < _subject_count; i++) {
 			_tree.insert(_trace.subject_info(_subjects[i]), _subjects[i]);
 		}
 
diff --git a/repos/gems/src/lib/vfs/ttf/glyphs_file_system.h b/repos/gems/src/lib/vfs/ttf/glyphs_file_system.h
index ed1fb10395..cd752119a6 100644
--- a/repos/gems/src/lib/vfs/ttf/glyphs_file_system.h
+++ b/repos/gems/src/lib/vfs/ttf/glyphs_file_system.h
@@ -73,7 +73,7 @@ class Vfs::Glyphs_file_system : public Vfs::Single_file_system
 						Glyph_header const header(glyph);
 
 						char const * const src = (char const *)&header + byte_offset;
-						size_t const len = min(sizeof(header) - byte_offset, count);
+						size_t const len = min(sizeof(header) - (size_t)byte_offset, (size_t)count);
 						memcpy(dst, src, len);
 
 						dst         += len;
@@ -87,12 +87,12 @@ class Vfs::Glyphs_file_system : public Vfs::Single_file_system
 					 * continue working with 'alpha_offset', which is the first
 					 * offset of interest within the array of alpha values.
 					 */
-					size_t const alpha_offset = byte_offset - sizeof(Glyph_header);
+					size_t const alpha_offset = (size_t)byte_offset - sizeof(Glyph_header);
 					size_t const alpha_values_len = 4*glyph.width*glyph.height;
 
 					if (alpha_offset < alpha_values_len) {
 						char const * const src = (char const *)glyph.values + alpha_offset;
-						size_t const len = min(alpha_values_len - alpha_offset, count);
+						size_t const len = min(alpha_values_len - alpha_offset, (size_t)count);
 						memcpy(dst, src, len);
 						out_count += len;
 					}
diff --git a/repos/gems/src/lib/vfs/ttf/vfs.cc b/repos/gems/src/lib/vfs/ttf/vfs.cc
index faded3df1f..f6af223dda 100644
--- a/repos/gems/src/lib/vfs/ttf/vfs.cc
+++ b/repos/gems/src/lib/vfs/ttf/vfs.cc
@@ -77,7 +77,7 @@ struct Vfs_ttf::Local_factory : File_system_factory, Watch_response_handler
 		Font_config(Xml_node const &config)
 		:
 			path(config.attribute_value("path", Directory::Path())),
-			size(config.attribute_value("size_px", 16.0)),
+			size((float)config.attribute_value("size_px", 16.0d)),
 			cache_limit({config.attribute_value("cache", Number_of_bytes())})
 		{ }
 	} _font_config;
diff --git a/repos/gems/src/server/file_terminal/main.cc b/repos/gems/src/server/file_terminal/main.cc
index e36002b038..03e2465dcd 100644
--- a/repos/gems/src/server/file_terminal/main.cc
+++ b/repos/gems/src/server/file_terminal/main.cc
@@ -22,11 +22,14 @@
 #include <terminal_session/terminal_session.h>
 
 /* libc includes */
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wconversion"
 #include <unistd.h>
 #include <sys/types.h>
 #include <sys/select.h>
 #include <stdio.h>
 #include <fcntl.h>
+#pragma GCC diagnostic pop  /* restore -Wconversion warnings */
 
 
 class Open_file
diff --git a/repos/gems/src/server/gui_fader/alpha_dither_painter.h b/repos/gems/src/server/gui_fader/alpha_dither_painter.h
index c54b212ab2..dbe018f496 100644
--- a/repos/gems/src/server/gui_fader/alpha_dither_painter.h
+++ b/repos/gems/src/server/gui_fader/alpha_dither_painter.h
@@ -49,9 +49,11 @@ struct Alpha_dither_painter
 
 			for (dst = dst_line, w = clipped.w(); w--; dst++, x++) {
 
-				int const v = Genode::Dither_matrix::value(x, y) << 13;
+				using namespace Genode;
 
-				dst->pixel = Genode::min(255, Genode::max(0, (fade - v) >> 16));
+				int const v = Dither_matrix::value(x, y) << 13;
+
+				dst->pixel = (uint8_t)min(255, max(0, (fade - v) >> 16));
 			}
 
 			y++;
@@ -88,15 +90,17 @@ struct Alpha_dither_painter
 
 			for (dst = dst_line, src = src_line, w = clipped.w(); w--; dst++, src++, x++) {
 
+				using namespace Genode;
+
 				/*
 				 * Multiply texture alpha value with fade value, dither the
 				 * result.
 				 */
 
 				int const a = (((int)src->pixel)*fade);
-				int const v = Genode::Dither_matrix::value(x, y) << 13;
+				int const v = Dither_matrix::value(x, y) << 13;
 
-				dst->pixel = Genode::min(255, Genode::max(0, (a - v) >> 16));
+				dst->pixel = (uint8_t)min(255, max(0, (a - v) >> 16));
 			}
 
 			y++;
diff --git a/repos/gems/src/server/gui_fader/main.cc b/repos/gems/src/server/gui_fader/main.cc
index ad85ab5a06..655259fdf0 100644
--- a/repos/gems/src/server/gui_fader/main.cc
+++ b/repos/gems/src/server/gui_fader/main.cc
@@ -441,14 +441,14 @@ struct Gui_fader::Main
 
 	enum { PERIOD = 20 };
 
-	unsigned long alpha = 0;
+	unsigned alpha = 0;
 
-	unsigned long fade_in_steps  = 0;
-	unsigned long fade_out_steps = 0;
+	unsigned fade_in_steps  = 0;
+	unsigned fade_out_steps = 0;
 
 	bool initial_fade_in = true;
 
-	unsigned long initial_fade_in_steps  = 0;
+	unsigned initial_fade_in_steps  = 0;
 
 	Genode::uint64_t curr_frame() const { return timer.elapsed_ms() / PERIOD; }
 
@@ -471,7 +471,7 @@ struct Gui_fader::Main
 	void handle_timer()
 	{
 		Genode::uint64_t frame = curr_frame();
-		if (gui_session.animate(frame - last_frame))
+		if (gui_session.animate((unsigned)(frame - last_frame)))
 			timer.trigger_once(PERIOD);
 
 		last_frame = frame;
@@ -502,7 +502,7 @@ void Gui_fader::Main::handle_config_update()
 
 	Genode::Xml_node config_xml = config.xml();
 
-	unsigned long new_alpha = alpha;
+	unsigned new_alpha = alpha;
 	if (config_xml.has_attribute("alpha"))
 		config_xml.attribute("alpha").value(new_alpha);
 
@@ -515,7 +515,7 @@ void Gui_fader::Main::handle_config_update()
 
 		bool const fade_in = (new_alpha > alpha);
 
-		int const steps =
+		unsigned const steps =
 			fade_in ? (initial_fade_in ? initial_fade_in_steps : fade_in_steps)
 			        : fade_out_steps;
 
diff --git a/repos/gems/src/server/terminal/session.h b/repos/gems/src/server/terminal/session.h
index 50547ed420..74c4d0cc87 100644
--- a/repos/gems/src/server/terminal/session.h
+++ b/repos/gems/src/server/terminal/session.h
@@ -100,9 +100,9 @@ class Terminal::Session_component : public Rpc_object<Session, Session_component
 		{
 			char const *src = _io_buffer.local_addr<char const>();
 
-			unsigned const max = min(num_bytes, _io_buffer.size());
+			size_t const max = min(num_bytes, _io_buffer.size());
 
-			unsigned i = 0;
+			size_t i = 0;
 			for (Utf8_ptr utf8(src); utf8.complete() && i < max; ) {
 
 				_character_consumer.consume_character(
@@ -121,7 +121,7 @@ class Terminal::Session_component : public Rpc_object<Session, Session_component
 			/* we don't support UTF-8 sequences split into multiple writes */
 			if (i != num_bytes) {
 				warning("truncated UTF-8 sequence");
-				for (unsigned j = i; j < num_bytes; j++)
+				for (size_t j = i; j < num_bytes; j++)
 					warning("(unhandled value ", Hex(src[j]), ")");
 			}
 
diff --git a/repos/gems/src/server/wm/decorator_gui.h b/repos/gems/src/server/wm/decorator_gui.h
index d383ef2c8f..0804ec78de 100644
--- a/repos/gems/src/server/wm/decorator_gui.h
+++ b/repos/gems/src/server/wm/decorator_gui.h
@@ -232,7 +232,7 @@ struct Wm::Decorator_gui_session : Genode::Rpc_object<Gui::Session>,
 
 		case Command::OP_TITLE:
 			{
-				unsigned long id = 0;
+				unsigned id = 0;
 				Genode::ascii_to(cmd.title.title.string(), id);
 
 				if (id > 0)
diff --git a/repos/gems/src/server/wm/main.cc b/repos/gems/src/server/wm/main.cc
index 43b456178d..92bb23d329 100644
--- a/repos/gems/src/server/wm/main.cc
+++ b/repos/gems/src/server/wm/main.cc
@@ -73,7 +73,7 @@ struct Wm::Main : Pointer::Tracker
 			if (!focus_rom.valid())
 				return;
 
-			unsigned long win_id = 0;
+			unsigned win_id = 0;
 
 			Xml_node(focus_rom.local_addr<char>()).sub_node("window")
 				.attribute("id").value(win_id);
@@ -97,10 +97,10 @@ struct Wm::Main : Pointer::Tracker
 
 		resize_request_rom.xml().for_each_sub_node("window", [&] (Xml_node window) {
 
-			unsigned long const
-				win_id = window.attribute_value("id",     0UL),
-				width  = window.attribute_value("width",  0UL),
-				height = window.attribute_value("height", 0UL);
+			unsigned const
+				win_id = window.attribute_value("id",     0U),
+				width  = window.attribute_value("width",  0U),
+				height = window.attribute_value("height", 0U);
 
 			gui_root.request_resize(win_id, Area(width, height));
 		});
diff --git a/repos/gems/src/server/wm/window_registry.h b/repos/gems/src/server/wm/window_registry.h
index 10465726e9..586e9e7b6e 100644
--- a/repos/gems/src/server/wm/window_registry.h
+++ b/repos/gems/src/server/wm/window_registry.h
@@ -213,7 +213,7 @@ class Wm::Window_registry
 
 		Id create()
 		{
-			Window * const win = new (_alloc) Window(_window_ids.alloc());
+			Window * const win = new (_alloc) Window((unsigned)_window_ids.alloc());
 
 			_windows.insert(win);
 
diff --git a/repos/gems/src/test/magic_ring_buffer/main.cc b/repos/gems/src/test/magic_ring_buffer/main.cc
index deb94bdfff..ef3663ebab 100644
--- a/repos/gems/src/test/magic_ring_buffer/main.cc
+++ b/repos/gems/src/test/magic_ring_buffer/main.cc
@@ -26,23 +26,22 @@ void Component::construct(Genode::Env &env)
 
 	log("--- magic ring buffer test, ", ring_buffer.capacity(), " int ring ---");
 
+	size_t const count = ring_buffer.capacity()/3;
 
-	int const count = ring_buffer.capacity()/3;
+	size_t total = 0;
 
-	int total = 0;
-
-	for (int j = 0; j < 99; ++j) {
-		for (int i = 0; i < count; ++i) {
-			ring_buffer.write_addr()[i] = i;
+	for (size_t j = 0; j < 99; ++j) {
+		for (size_t i = 0; i < count; ++i) {
+			ring_buffer.write_addr()[i] = (int)i;
 		}
 
 		ring_buffer.fill(count);
 
-		for (int i = 0; i < count; ++i) {
-			if (ring_buffer.read_addr()[i] != i) {
+		for (size_t i = 0; i < count; ++i) {
+			if (ring_buffer.read_addr()[i] != (int)i) {
 				error("ring buffer corruption, ",
 				      ring_buffer.read_addr()[i], " != ", i);
-				env.parent().exit(total+i);
+				env.parent().exit((int)(total + i));
 				return;
 			}
 		}
diff --git a/repos/gems/src/test/text_painter/main.cc b/repos/gems/src/test/text_painter/main.cc
index 856de2a57a..dd93ab1640 100644
--- a/repos/gems/src/test/text_painter/main.cc
+++ b/repos/gems/src/test/text_painter/main.cc
@@ -111,8 +111,9 @@ struct Test::Main
 		/* test horizontal subpixel positioning */
 		_surface.clip(Rect(Point(90, 15), Area(100, 300)));
 		Box_painter::paint(_surface, Rect(Point(0, 0), _size), Color(150, 20, 10));
+		float const font_3_h = (float)_font_3.bounding_box().h();
 
-		for (float x = 90, y = -30; y < (int)_size.h() + 30; x += 0.2, y += _font_3.bounding_box().h())
+		for (float x = 90, y = -30; y < (float)_size.h() + 30; x += 0.2f, y += font_3_h)
 			Text_painter::paint(_surface,
 			                    Text_painter::Position(x, y), _font_3,
 			                    Color(255, 255, 255),
@@ -121,7 +122,7 @@ struct Test::Main
 		_surface.clip(Rect(Point(90, 320), Area(100, 300)));
 		Box_painter::paint(_surface, Rect(Point(0, 0), _size), Color(255, 255, 255));
 
-		for (float x = 90, y = 300; y < (int)_size.h() + 30; x += 0.2, y += _font_3.bounding_box().h())
+		for (float x = 90, y = 300; y < (float)_size.h() + 30; x += 0.2f, y += font_3_h)
 			Text_painter::paint(_surface,
 			                    Text_painter::Position(x, y), _font_3,
 			                    Color(0, 0, 0),
@@ -136,7 +137,8 @@ struct Test::Main
 			{
 				auto fill_segment = [&] (long x1, long y1, long x2, long)
 				{
-					for (long i = x1>>8; i < x2>>8; i++) value[i] = min(255, y1>>8);
+					for (long i = x1>>8; i < x2>>8; i++)
+						value[i] = (unsigned char)min(255L, y1>>8);
 				};
 
 				bezier(0, 0, 0, 130<<8, 256<<8, 260<<8, fill_segment, 7);
@@ -170,7 +172,7 @@ struct Test::Main
 			Genode::uint64_t const end_us = timer.elapsed_us();
 			unsigned long num_glyphs = strlen(vfs_text_string)*ITERATIONS;
 
-			log("uncached painting: ", (float)(end_us - start_us)/num_glyphs, " us/glyph");
+			log("uncached painting: ", (float)(end_us - start_us)/(float)num_glyphs, " us/glyph");
 			_refresh();
 		}
 
@@ -188,13 +190,13 @@ struct Test::Main
 				Text_painter::paint(_surface,
 				                    Text_painter::Position(260 + (i*83  % 500),
 				                                           320 + (i*153 % 400)),
-				                    cached_font, Color(30, limit_kib, 150 + i*73),
+				                    cached_font, Color(30, (int)limit_kib, 150 + i*73),
 				                    "Glyphs obtained from VFS");
 
 			Genode::uint64_t const end_us = timer.elapsed_us();
 			unsigned long num_glyphs = strlen(vfs_text_string)*iterations;
 
-			log("cached painting:   ", (float)(end_us - start_us)/num_glyphs, " us/glyph"
+			log("cached painting:   ", (float)(end_us - start_us)/(float)num_glyphs, " us/glyph"
 			    " (", cached_font.stats(), ")");
 			_refresh();
 		}