United States customary units

**U.S. customary units** are the main defacto official 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).  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:

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 the majority Americans still primarily use the old units for daily purposes and most government documents list measurements in the US customary system only. On the other hand, world trade is conducted using the metric system and except for the US and Liberia, the world uses the metric system for almost all purposes.

## Length

|unit||equal to||Metric|
| --- | --- | --- | --- | --- |
|1 thou or mil|inch|0.0254 mm|||
|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 ft<sup>2</sup>)||0.0929 m<sup>2</sup>|||
|1 square chain (sq ch or ch<sup>2</sup>)|4356 sq ft|404.7 m<sup>2</sup>|||
|1 acre|10 sq ch|4 047 m<sup>2</sup>|||
|1 section|640 acres|2.6 km<sup>2</sup>|||
|1 (survey) township (twp)|36 sections|93.2 km<sup>2</sup>|||

## Volume

|Unit||Equal to||Metric|
| --- | --- | --- | --- | --- |
|1 cubic inch (cu in) or (in<sup>3</sup>)||16 mL|||
|1 cubic foot (cu ft) or (ft<sup>3</sup>)|1728 cu in|28 L|||
|1 cubic yard (cu yd) or (yd<sup>3</sup>)|27 cu ft|766.55 L|||
|1 acre-foot (acre ft)|1613.333 cu yd|1,233,000 L|||

|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|||

|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

|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|||
|Unit||Equal to||Metric|
| --- | --- | --- | --- | --- |
|1 grain (gr)||65 mg|||
|1 pennyweight (dwt)|24 gr|1.55517 g|||
|1 troy ounce (oz t)|20 dwt|31.1035 g|||
|1 troy pound (lb t)|12 oz t|373.242 g|||

## Related pages

- Units of measurement