Weights and Measures: Table
Some Non-SI Units Used in North America |
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Unit |
Definition |
SI Value |
|
LENGTH |
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nautical mile |
air & sea measure¹ |
1.852 km |
|
furlong |
220 yd |
201.2 m |
|
mile |
1760 yd |
1.609 km |
|
arpent |
180 Paris feet |
58.47 m |
|
yard |
3 feet |
0.9144 m |
|
foot |
12 inches |
0.3048 m |
|
inch |
1/36 yard |
25.4 mm |
|
AREA |
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acre (survey) |
4840 sq yards (survey) |
4047 m2 |
|
acre (commercial) |
4000 sq yards (commercial) |
3344.51 m2 |
|
MASS |
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Avoirdupois: |
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long ton |
2240 lb |
1.016 t |
|
short ton |
2000 lb |
0.907 t |
|
pound |
16 ounces |
0.453 kg |
|
ounce |
1/12 ancient Roman pound |
28.35 g |
|
Troy: |
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pound |
12 oz |
0.3732 kg |
|
ounce |
20 dwt |
31.10 g |
|
pennyweight (dwt) |
24 g |
1.555 g |
|
CAPACITY |
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barrel (bbl) |
36 gal |
163.7 L |
|
barrel [US]² |
42 US gal |
159.0 L |
|
bushel (bu) |
4 pecks |
36.37 L |
|
peck |
2 gal |
9.092 L |
|
gallon (gal) |
|
4.54609 L |
|
gallon [US] |
231 cu in |
3.785 L |
|
quart (qt) |
¼ gal |
1.137 L |
|
pint (pt) |
½ qt |
568.3 ml |
|
MISCELLANEOUS |
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British Thermal Unit (Btu)³ |
|
1055 J |
|
carat |
weight for precious stones |
200 mg |
|
Fahrenheit (°F) |
|
°F = (C x 1.8) + 32 °C = (F - 32) x 5/9 |
horsepower
550 ft lb/sec
745.7 W
knot
1 naut mi/hr
0.5144 m/s
¹ Based on the length of a minute of arc of a great circle; differs
because the Earth is not a perfect sphere
² This is the barrel used in the oil industry
³ The amount of heat required to raise the temperature of a pound of water one degree Fahrenheit near 39.2°F
For more information see the article WEIGHTS AND MEASURES.