diff --git a/repos/os/include/util/geometry.h b/repos/os/include/util/geometry.h
index 4e23bea507..1637b9d962 100644
--- a/repos/os/include/util/geometry.h
+++ b/repos/os/include/util/geometry.h
@@ -105,7 +105,7 @@ class Genode::Area
 
 		bool valid() const { return _w > 0 && _h > 0; }
 
-		size_t count() const { return _w*_h; }
+		size_t count() const { return (size_t)_w*(size_t)_h; }
 
 		/**
 		 * Operator for testing non-equality of two areas