United States customary units

U.S. customary units is the main system of units of measurement used to measure things in the United States and U.S. territories (except in Puerto Rico and Guam, where the metric system is also officially used and is dominant).^[1] The system of Imperial units, on which the U.S. customary units are based, is very similar but there are some differences.

Length or distance units include the inch, foot, yard and mile.

Land units include square miles (2589998.47032 square meter) and acres (4046.8726 square meter).

Common volume units are the teaspoon, tablespoon (3 teaspoons), fluid ounce (two tablespoons), cup (8 ounces), pint (2 cups, or 16 fluid ounces), quart (2 pints, or 32 fluid ounces), US gallon (16 cups, 128 fluid ounces, or 3.8 liters).

A barrel is the unit to measure oil.

Temperature is measured in degrees Fahrenheit (°F). Here is a formula to convert from °C to °F: [math]\displaystyle{ \frac{9}{5}C+32 }[/math]^[a]

Units of weight and mass include the pound (453.6 grams), which contains 16 ounces. This should not be confused with the British pound which is a type of money. The different uses of the word pound can cause confusion. Different sizes of ounce are also in use.

Some people have been trying to replace these units with the metric system since the 1820s. Much infrastructure in the United States and British Empire was built in past centuries using the old measures. During the 20th century some sectors such as science, medicine and the military of the United States converted to metric but Americans still use the old units for daily purposes. On the other hand, world trade is conducted using the metric system and except for the US, the world uses the metric system for almost all purposes.

Length

unit	equal to	Metric
1 point (p)		0.4 mm
1 pica (P)	12 points	4.2 mm
1 inch (in)	6 picas	2.54 cm
1 foot (ft)	12 inches	30.48 cm
1 yard (yd)	3 feet	0.9144 m
1 mile (mi)	1760 yards	1.609344 km

Area

Unit	Equal to	Metric
1 square (survey) foot (sq ft or ft²)		0.0929 m²
1 square chain (sq ch or ch²)	4356 sq ft	404.7 m²
1 acre	10 sq ch	4 047 m²
1 section	640 acres	2.6 km²
1 (survey) township (twp)	36 sections	93.2 km²

Volume

Capacity Volume
Unit	Equal to	Metric
1 cubic inch (cu in) or (in³)		16 mL
1 cubic foot (cu ft) or (ft³)	1728 cu in	28 L
1 cubic yard (cu yd) or (yd³)	27 cu ft	766.55 L
1 acre-foot (acre ft)	1613.333 cu yd	1,233,000 L

Liquid volume
Unit	Equal to	Metric
1 minim (min)	1 drop	0.1 mL
1 US fluid dram (fl dr)	60 min	3.7 mL
1 teaspoon (tsp)	80 min	4.92892 mL
1 tablespoon (Tbsp)	3 tsp	14.7868 mL
1 US fluid ounce (fl oz)	2 Tbsp	29.5735 mL
1 US shot (jig)	3 Tbsp	44 mL
1 US gill (gi)	4 fl oz	118.294 mL
1 US cup (cp)	2 gi	240 mL
1 (liquid) US pint (pt)	2 cp	473.176 mL
1 (liquid) US quart (qt)	2 pt	0.946353 L
1 (liquid) US gallon (gal)	4 qt	3.78541 L
1 (liquid) barrel (bbl)	31.5 gal	119.2405 L
1 oil barrel (bbl)	42 gal	158.987 L
1 hogshead	63 gal	238.481 L

Dry Volume
Unit	Equal to	Metric
1 (dry) pint (pt)		0.6 L
1 (dry) quart (qt)	2 pt	1.1 L
1 (dry) gallon (gal)	4 qt	4.4 L
1 peck (pk)	2 gal	8 L
1 bushel (bu)	4 pk	35 L
1 (dry) barrel (bbl)	3.281 bu	110 L

Mass and weight

Avoirdupois
Unit	Equal to	Metric
1 grain (gr)		65 mg
1 dram (dr)	27 11⁄32 gr	1.8 g
1 ounce (oz)	16 dr	28.3495 g
1 pound (lb)	16 oz	453.592 g
1 US hundredweight (cwt)	100 lb	45.3592 kg
1 long hundredweight	112 lb	50.802345 kg
1 short ton	20 US cwt	907.185 kg
1 long ton	20 long cwt	1,016.047 kg