A US gallon is 3.785 liters (NIST: 3.785412 L). Multiply gallons by 3.785 to get liters, and divide liters by 3.785 to get gallons. So 2 gallons is 7.57 L and 10 L is 2.64 gal. The British imperial gallon is larger at exactly 4.54609 L, so the country matters.
How many liters are in a gallon?
NIST lists the US gallon as 3.785412 liters and the imperial gallon, used in the UK and historically in Canada, as exactly 4.54609 liters. The liter is a metric volume unit equal to 0.001 cubic meters. The two gallons differ by a factor of 4.54609 ÷ 3.785412 = 1.2009, so an imperial gallon holds about 20% more. See US gallon and imperial gallon for the definitions.
Formulas
liters = US gallons × 3.785
US gallons = liters ÷ 3.785 (or liters × 0.2642)
liters = imperial gallons × 4.546
imperial gallons = liters ÷ 4.546
The converters gallons to liters and liters to gallons handle any value.
Gallons to liters chart
| Gallons | US liters | Imperial liters |
|---|---|---|
| 1/4 | 0.95 | 1.14 |
| 1/2 | 1.89 | 2.27 |
| 1 | 3.79 | 4.55 |
| 2 | 7.57 | 9.09 |
| 2.5 | 9.46 | 11.37 |
| 3 | 11.36 | 13.64 |
| 5 | 18.93 | 22.73 |
| 10 | 37.85 | 45.46 |
| 15 | 56.78 | 68.19 |
| 20 | 75.71 | 90.92 |
Liters to gallons chart
| Liters | US gallons | Imperial gallons |
|---|---|---|
| 1 | 0.264 | 0.220 |
| 2 | 0.528 | 0.440 |
| 3 | 0.793 | 0.660 |
| 4 | 1.057 | 0.880 |
| 5 | 1.321 | 1.100 |
| 10 | 2.642 | 2.200 |
| 20 | 5.283 | 4.399 |
| 40 | 10.567 | 8.799 |
| 50 | 13.209 | 10.998 |
Worked examples
Example 1: a gallon of water in liters
A one-gallon jug holds 3.785 L, or 3,785 mL. Drinking 2 L a day is 2 ÷ 3.785 = 0.53 gal, a little over half a gallon.
Example 2: a fish tank
A 20-gallon aquarium holds 20 × 3.785412 = 75.7 L. A tank described as 75 L is therefore about 19.8 US gallons.
Example 3: a fuel tank
A car with a 13.2-gallon US tank holds 13.2 × 3.785412 = 50.0 L. A European car with a 50 L tank holds 50 ÷ 3.785412 = 13.2 US gallons.
Example 4: the wrong gallon
Ten imperial gallons are 45.46 L, while 10 US gallons are 37.85 L, a gap of 7.6 L. A UK fuel figure read as US gallons understates the volume by a sixth (3.785 ÷ 4.546 = 0.833).
Example 5: from a 4-liter jug
A 4 L jug is 4 ÷ 3.785412 = 1.057 US gallons, so it holds 5.7% more than a US gallon but 12% less than an imperial one (4 ÷ 4.54609 = 0.880).
Why do the two gallons differ?
The US gallon is defined as 231 cubic inches, and 231 × 2.54³ cm³ equals 3,785.41 mL. The imperial gallon is defined directly in metric terms at 4.54609 liters. The imperial fluid ounce (28.41 mL) is smaller than the US one (29.57 mL), although the imperial gallon holds 160 of them against 128. The gallon in ounces guide breaks the US gallon into quarts, pints, cups and fluid ounces.
Quick ways to remember
- 1 US gallon is about 3.8 L; 4 L is a decent upper estimate.
- 1 L is about 0.26 US gallons, or a little more than a quart (1.057 US quarts; see liters to quarts).
- Imperial is about 4.5 L per gallon.
- Check the country before converting a gallon figure for fuel or paint. The metric vs imperial guide lists other units with near-twin names.
For smaller volumes, liters to milliliters and liters to oz take over; the next guide covers ounces in a liter.