English Unit Abbreviations

Abbreviation	Unit of Measurement
bbl.	barrel
cu.	cubic
doz.	dozen
F., F	Fahrenheit
fl. oz.	fluid ounce
ft.	foot
gal.	gallon
gr.	grain
gr., gro.	gross
in.	inch
k., kt.	karat
k., kt.	knot
lb.	pound
LT, L.T.	long ton
mi.	mile
mph	miles per hour
n.m.	nautical miles
oz.	ounce
pt.	pint
qt.	quart
sq.	square
rpm	revolutions per minute
T., T	ton
T.	tablespoon in some cookbooks
t.	teaspoon in some cookbooks
tbsp.	tablespoon
tsp.	teaspoon
yd.	yard

The single hatch mark ' can stand for foot or a geographical minute (a minute of longitude or latitude). The double hatch mark " can stand for inch or geographical second (a second of longitude or latitude). So 5'6" would mean five feet, six inches. 42°24'54" N. would mean 42 degrees, 24 minutes, 54 seconds north.

 

Metric Abbreviations

Abbreviation	Unit of Measurement
b	bit
B	byte
C	Celsius, Centigrade
cc or cm³	cubic centimeter (cm³ is standard)
cm	centimeter
G,GB	gigabyte (GB is standard)
g, gr	gram (g is standard)
ha	hectare
K	Kelvin
K, KB	kilobyte (KB is standard)
kg	kilogram
kl	kiloliter
km	kilometer
l	liter
m	meter
M, MB	megabyte (MB is standard)
mcg or µg	microgram ( µg is standard)
mg	milligram
ml	milliliter
mm	millimeter
MT	metric ton
t, T	metric ton
w, W	watt (W is standard)
kw, kW	kilowatt (kW is standard)
kwh, kWh	kilowatt-hour (kWh is standard)

Since the metric system uses standard prefixes, you can easily figure out most other metric abbreviations; for example, cl would be centiliter.

The Greek letter µ (mu) is often used to show the prefix micro, especially in scientific publications. For example, µg would be the same as mcg, and µl would be microliter. When by itself, µ stands for micron. mµ means millimicron, and µµ means micromicron (a millionth of a micron).

The prefix nano means "billionth," and is usually represented by the letter n, as in ns for nanosecond.

To abbreviate most square and cubic units in the metric system, add the exponent ² for square and the exponent ³ for cubic. For example, m² means square meter, and mm³ means cubic millimeter. If you use this notation, use it consistently: Use cm³ rather than cc for cubic centimeter.
In standard scientific notation, the word per is represented by a virgule. So km/h is kilometers per hour.
For international standards including abbreviations for very tiny and very large units, see http://physics.nist.gov/cuu/Units/ or http://physics.nist.gov/cuu/Units/checklist.htm.