The following tables list all of the available unit prefixes, and many of the most
commonly used units in simulations at the NASA, Johnson Space Center - Engineering Branch.
Tables of units are provided for measuring time, length,
angle, mass, force, volt, current,
resistance, temperature, energy,
power, pressure, volume, and frequency.
Each of the rows in each of the tables contain a list of identifiers that refer to a
particular unit. Each of the identifiers in a list is synonymous. Also, characters
between brackets are optional. For example, "s", "second", "seconds" are treated as
being identical.
It is important to note that these tables are not complete lists of all available units.
If you're really curious, or if you just can't find the units you need, you could run
udunits2 -h on the command line, follow the default database path listed at the bottom
of the help text, and examine the (fairly easy to read) UDUNITS2 xml database files.
You could also use udunits2 with the -H option to determine whether the units you need exist, by guessing.
Unit Prefixes
Prefix
Value
Y, yotta
1e24
Z, zetta
1e21
E, exa
1e18
P, peta
1e15
T, tera
1e12
G, giga
1e9
M, mega
1e6
k, kilo
1e3
h, hecto
100
da, deka
10
d, deci
0.1
c, centi
0.01
m, milli
1e-3
μ, u, micro
1e-6
n, nano
1e-9
p, pico
1e-12
f, femto
1e-15
a, atto
1e-18
z, zepto
1e-21
y, yocto
1e-24
###Common Predefined Units
Time
Unit Identifier
s, second[s]
ms, millisecond[s]
μs, microsecond[s]
min, minute[s]
h, hour[s]
d, day[s]
Length
Unit Identifier
m, meter[s]
au, astronomical_unit[s]
nmile, nautical_mile[s]
ft, foot, feet
in, inch[es]
yd, yard[s]
mi, mile[s]
km, kilometer[s]
cm, centimeter[s]
mm, millimeter[s]
um, μm, micrometer[s]
Angle
Unit Identifier
rad, radian[s]
°, degree[s]
′, arcminute[s]
″, arcsecond[s]
Mass
Unit Identifier
kg, kilogram[s]
g, gram[s]
lb, pound[s]
slug, slug[s]
NOTE: For Trick 13 and earlier, use 'sl' instead of 'slug'.