| gallon | |
|---|---|
 A one-US-gallon gas can showing "U.S. Gallon" marking (for American use), imperial gallons (for British use), and litres (for Canadian use) | |
| General information | |
| Unit of | Volume |
| Symbol | gal |
| Conversions (imperial) | |
| 1 imp gal in ... | ... is equal to ... |
| SI units | 4.54609 L |
| US customary units | ≈ 1.200950 US gal |
| US customary units | ≈ 277.4194 in3 |
| Conversions (US) | |
| 1 US gal in ... | ... is equal to ... |
| SI units | 3.785411784 L |
| Imperial units | ≈ 0.8326742 imp gal |
| Imperial units | 231 in3 |
| US dry gallon | ≈ 0.859367 US dry gal |
The gallon is a unit of volume in British imperial units and United States customary units. Three different versions are in current use:
- the imperial gallon (imp gal), defined as 4.54609 litres, which is or was used in the United Kingdom, Ireland, Canada, Australia, New Zealand, and some Caribbean countries;
- the US liquid gallon (US gal), defined as 231 cubic inches (exactly 3.785411784 L),[1] which is used in the United States and some Latin American and Caribbean countries; and
- the US dry gallon, defined as 1⁄8 US bushel (exactly 4.40488377086 L).
There are two pints in a quart and four quarts in a gallon. Different sizes of pints account for the different sizes of the imperial and US gallons.
The IEEE standard symbol for both US (liquid) and imperial gallon is gal,[2] not to be confused with the gal (symbol: Gal), a CGS unit of acceleration.
- ^ Thompson, E Ambler; Taylor, Barry N (2008). Guide for the use of the International System of Units (SI). National Institute of Standards and Technology. doi:10.6028/nist.sp.811e2008.
- ^ IEEE Std 260.1–2014