IT and communication - Mathematics & physics and IT:

Go metric!

Note: ConvertIt.com provides an online Measurement Converter.

The following lists give metric (or SI) equivalents of non-metric units. Each row specifies the name of the unit, the abbreviation(s) of the unit, and the metric equivalent. The metric measures are given using the standardized abbreviations:

m	micrometre; 1 mm = 1000 m; note:  often replaced by letter u
mm	millimetre; 1 m = 1000 mm
m	metre (US spelling: meter)
km	kilometre (1000 m)

mm	square millimetre; 1 m = 1 000 000 mm
cm	square centimetre; 1 m = 10 000 cm
m	square metre
a	are (100 m)
km	square kilometre (1 000 000 m)

ml	millilitre; 1 l = 1000 ml; equivalent to cubic centimetre (cm)
l	litre (US spelling: liter); 1 m = 1000 l; equiv. to cubic decimetre
m	cubic metre

mg	milligramme; 1 g = 1000 mg
g	gramme (US spelling: gram)
kg	kilogramme (1000 g)
Mg	megagramme (1000 kg); equivalent to metric ton (t)

Linear measure

(didot) point			376 m
pica em				  4.512 mm
inch		in., "		 25.40 mm
foot		ft.		304.80 mm
yard		yd.		914.40 mm
(statute) mile	mi.		  1.609344 km
nautical mile	nm		  1.852 km

Surface measure

square inch	sq.in.		645.2 mm
square foot	sq.ft.		930 cm
square yard	sq.yd.		  0.836 m
acre				 40.469 a	
claim				 59.5 a
square mile	sq.mi.		  2.590 km

Volume (and liquid) measure

cubic inch	cu.in.		 16.387 ml
fluid ounce	oz.fl., fl.oz.	 29.57 ml
imperial pint	imp.pt.		568 ml
US. quart	US.qt.		946 ml
imperial quart	imp.qt.		  1.137 l
US. gallon	US.gal.		  3.785 l
imperial gallon	imp.gal.	  4.546 l
cubic foot	cu.ft.		 28 l
US. bushel			 35.239 l
imperial bushel			 36.369 l
barrel				159 l
quarter		qr.		281.912 l
cubic yard	cu.yd.		765 l
register ton	RT		  2.832 m

Weights

grain			gr.		 65 mg
pennyweight		dwt.		  1.555 g
avoirdupois ounce	oz.		 28.35 g
troy ounce		tr.oz.		 31.1035 g
fine ounce				 31.2 g
metric carat				200 mg
(avoirdupois) pound	lb.		453.592 g
stone			st.		  6.350 kg
quarter			qr.		 12.701 kg
cental					 45.359 kg
US. hundredweight			 45.359 kg
hundredweight		cwt.		 50.802 kg
short ton		sh.tn.		907.185 kg
long ton, gross ton	l.tn.		  1.016 Mg

Other measures

British thermal unit	Btu		  1.0548 kJ
therm					105.48 MJ
UK horsepower		hp		745.7 W
Fahrenheit degree	F		555.556 mK
Note: The zero point of the Fahrenheit scale is different from absolute zero temperature. Therefore, the above-mentioned rule applies as such only to temperature differences. Given a temperature measurement F in F, the corresponding quantity in kelvins is 0.5555556×F + 255.3722, and in the Celsius or centigrade scale it is (5/9)×(F-32).