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Weights and Measures

The words in dark type are the most commonly used in general speech.

METRIC

Units of length
    1 millimetre = 0.03937 inch
10 mm = 1 centimetre = 0.3937 inch
10 cm = 1 decimetre = 3.937 inches
10 dm = 1 metre = 39.37 inches
10 m = 1 decametre = 10.94 yards
10 dam = 1 hectometre = 109.4 yards
10 hm = 1 kilometre = 0.6214 mile

Units of weight
    1 milligram = 0.015 grain
10 mg = 1 centigram = 0.154 grain
10 cg = 1 decigram = 1.543 grains
10 dg = 1 gram = 15.43 grains
    = 0.035 ounce
10 g = 1 decagram = 0.353 ounce
10 dag = 1 hectogram = 3.527 ounces
10 hg = 1 kilogram = 2.205 pounds
100 kg = 1 tonne = 0.984 (long) ton
    (metric ton) = 2204.62 pounds

Units of capacity
    1 millilitre = 0.00176 pint
10 ml = 1 centilitre = 0.0176 pint
10 cl = 1 decilitre = 0.176 pint
10 dl = 1 litre = 1.76 pints
      = 0.22 UK gallon
10 l = 1 decalitre = 2.20 gallons
10 dal = 1 hectolitre = 22.0 gallons
10 hl = 1 kilolitre = 220.0 gallons

Square measure
1 square measure = 0.00155 square inch
100 mm2 = 1 square centimetre = 0.1550 square inch
100 cm2 = 1 square metre = 1.196 square yards
100 m2 = 1 are = 119.6 square yards
100 ares = 1 hectare = 2.471 acres
100 ha = 1 square kilometre = 247.1 acres

Cubic measure
1 cubic centimetre = 0.06102 cubic inch
1000 cm3 = 1 cubic decimetre = 0.03532 cubic foot
1000 dm3 = 1 cubic metre = 1.308 cubic yards

Circular measure
1 microradian = 0.206 seconds
1000 µrad = 1 milliradian = 3.438 minutes
1000 mrad = 1 radian = 57.296 degrees
  = 180/ π degrees

Metric Prefixes
 
Abbreviation
Factor
tera-
T
1012
giga-
G
109
mega-
M
106
kilo-
k
103
hecto-
h
102
deca-
da
101
deci-
d
10–1
centi-
c
10–2
milli-
m
10–3
micro-
μ
10–6
nano-
n
10–9
pico-
p
10–12
femto-
f
10–15
atto-
a
10-18

BRITISH AND AMERICAN

Units of length
    1 inch = 2.54 cm
12 inches = 1 foot = 0.3048 m
3 feet = 1 yard = 0.9144 m
5½ yards = 1 rod, pole, or perch = 5.029 m
22 yards = 1 chain = 20.12 m
10 chains = 1 furlong = 0.2012 km
8 furlongs = 1 mile = 1.609 km
6076.12 feet = 1 nautical mile = 1852 m

Units of weight
1 grain = 64.8 mg
1 dram = 1.772 g
16 drams = 1 ounce = 28.35 g
16 ounces = 1 pound = 0.4536 kg
14 pounds = 1 stone = 6.350 kg
2 stones = 1 quarter = 12.70 kg
4 quarters = 1 (long) hundredweight = 50.80 kg
20 hundredweight = 1 (long) ton = 1.016 tonnes
100 pounds = 1 (short) hundredweight = 45.36 kg
2000 pounds = 1 (short) ton = 0.9072 tonnes
 
The short hundredweight and ton are more common in the US.

Units of capacity
1 fluid ounce = 28.41 cm3
5 fluid ounces = 1 gill = 0.1421 dm3
4 gills = 1 pint = 0.5683 dm3
2 pints = 1 quart = 1.137 dm3
4 quarts = 1 (UK) gallon = 4.546 dm3
231 cubic inches = 1 (US) gallon = 3.785 dm3
8 gallons = 1 (UK) bushel = 36.369 dm3

Square measure
1 square inch = 645.16 mm2
144 square inches = 1 square foot = 0.0929 m2
9 square feet = 1 square yard = 0.8361 m2
4840 square yards = 1 acre = 4047 m2
640 acres = 1 square mile = 259 ha

Cubic measure
1 cubic inch = 16.39 cm3
1728 cubic inches = 1 cubic foot = 0.02832 m3
      = 28.32 dm3
27 cubic feet = 1 cubic yard = 0.7646 m3
      = 764.6 dm3

Circular measure
1 second = 4.868 µrad
60 seconds = 1 minute = 0.2909 mrad
60 minutes = 1 degree = 17.45 mrad
      = π/180 rad
45 degrees = 1 oxtant = π/4 rad
60 degrees = 1 sextant = π/3 rad
90 degrees = 1 quadrant or
1 right angle
= π/2 rad
360 degrees = 1 circle or
1 circumference
= 2π rad
1 grade or gon = 1/100th of a right angle = π/200 rad

US Dry measure
1 pint = 0.9689 UK pint = 0.5506 dm3
1 bushel = 0.9689 UK bushel = 35.238 dm3

US Liquid measure
1 fluid ounce = 1.0408 UK fluid ounces
  = 0.0296 dm3
16 fluid ounces = 1 pint = 0.8327 UK pint
  = 0.4732 dm3
8 pints = 1 gallon = 0.8327 UK gallon
  = 3.7853 dm3

Temperature
° Fahrenheit = (9/5 × x °C) + 32
° Celsius = 5/9 × (x °F – 32)