Convert liters to US gallons or gallons to liters, switch to UK imperial gallons when you need them, and see quarts and fluid ounces too.
Gas prices abroad are per liter, aquarium and fish tank specs mix both units, and plenty of drink bottles, motor oil jugs and paint cans list liters right beside gallons. Type in either box to go between liters and gallons. One catch: a US gallon and a UK (imperial) gallon aren’t the same size, and the UK one is about 20% bigger, so pick the right one with the buttons before you trust the answer.
How do I convert liters to gallons?
Divide liters by 3.785411784 to get US gallons, or multiply gallons by 3.785411784 to get liters. For UK imperial gallons, use 4.54609 instead. For example, a 20-liter water jug holds 20 ÷ 3.785 = 5.28 US gallons, but only 4.40 imperial gallons. A rough rule: 1 US gallon is a little under 4 liters.
Liters to gallons formula
UK gallons = liters ÷ 4.54609
1 US gal = 4 qt = 8 pt = 128 fl oz · 1 UK gal = 160 UK fl oz
Both gallons are defined exactly in liters. The US gallon comes from the old wine gallon of 231 cubic inches, while the imperial gallon was set in 1824 as the volume of 10 pounds of water. That history is why they ended up different.
Liters to gallons chart
| Liters | US gallons | US quarts | US fl oz | UK gallons |
|---|---|---|---|---|
| 0.5 L | 0.132 gal | 0.53 qt | 16.9 fl oz | 0.11 UK gal |
| 1 L | 0.264 gal | 1.06 qt | 33.8 fl oz | 0.22 UK gal |
| 2 L | 0.528 gal | 2.11 qt | 67.6 fl oz | 0.44 UK gal |
| 3 L | 0.793 gal | 3.17 qt | 101.4 fl oz | 0.66 UK gal |
| 4 L | 1.057 gal | 4.23 qt | 135.3 fl oz | 0.88 UK gal |
| 5 L | 1.321 gal | 5.28 qt | 169.1 fl oz | 1.1 UK gal |
| 10 L | 2.642 gal | 10.57 qt | 338.1 fl oz | 2.2 UK gal |
| 20 L | 5.283 gal | 21.13 qt | 676.3 fl oz | 4.399 UK gal |
| 50 L | 13.209 gal | 52.83 qt | 1,690.7 fl oz | 10.998 UK gal |
| 60 L | 15.85 gal | 63.4 qt | 2,028.8 fl oz | 13.198 UK gal |
| 100 L | 26.417 gal | 105.67 qt | 3,381.4 fl oz | 21.997 UK gal |
US vs UK measures at a glance
| Unit | US | UK imperial |
|---|---|---|
| Gallon | 3.785 L | 4.546 L |
| Quart | 946.4 mL | 1,136.5 mL |
| Fluid ounce | 29.57 mL | 28.41 mL |
Funny detail: the UK fluid ounce is actually smaller than the US one, even though the UK gallon is bigger. It’s because an imperial gallon holds 160 fl oz and a US gallon only 128.
How to use the Liters to Gallons Converter
Pick US or UK gallons
Leave it on US gallon for American labels, or switch to UK imperial gallon for British sources.
Type liters or gallons
Enter an amount in either box and the other one updates.
Read the result
See the converted volume, plus quarts, fluid ounces and milliliters.
Why is a US gallon exactly 231 cubic inches?
The US liquid gallon comes from the English wine gallon, fixed at 231 cubic inches by a statute passed in 1707 under Queen Anne. The American colonies kept that wine gallon after independence, while Britain later replaced its several gallons with the imperial gallon in 1824.
Once the inch was defined as exactly 2.54 centimeters in 1959, the US gallon became an exact metric amount: 231 × 16.387064 cm³ = 3.785411784 liters. The National Institute of Standards and Technology (NIST) publishes this value as the official conversion used in US trade and labeling.
The imperial gallon was originally the volume of 10 pounds of water. The Weights and Measures Act 1985 in the UK redefined it as exactly 4.54609 liters, so it no longer depends on water at all.
The US also has a rarely used dry gallon of 268.8025 cubic inches, about 4.405 liters. It survives mainly as the basis of the dry quart and the bushel, not on fuel pumps or milk jugs.
For smaller kitchen amounts, the same exact definitions sit behind the milliliters to fluid ounces converter.
How was the liter defined?
The liter was introduced in France in 1795 as the volume of a cube 10 centimeters on each side. In 1901 the General Conference on Weights and Measures (CGPM) changed it to the volume of one kilogram of pure water at its maximum density. Precise measurements later showed that this water liter was about 1.000028 cubic decimeter, a small but real mismatch.
In 1964 the CGPM went back to the original idea and declared the liter a special name for exactly one cubic decimeter. In 1979 it approved the capital letter L as a symbol alongside lowercase l, because the lowercase letter is easy to confuse with the number 1.
Today the liter is not an SI base unit but is accepted for use with the SI. That is why every conversion on this page is exact: a liter is 1,000 cm³, and a US gallon is 3,785.411784 cm³.
If you cook with metric recipes, the cups to ml converter uses the same cubic definitions.
How do you convert miles per gallon to liters per 100 km?
Most of the world rates fuel use in liters per 100 kilometers, which measures fuel burned for a fixed distance. Miles per gallon does the opposite and measures distance per fixed fuel, so the conversion is a division, not a multiplication.
- US mpg to L/100 km: 235.215 ÷ mpg
- UK mpg to L/100 km: 282.481 ÷ mpg
A car rated at 30 US mpg uses 235.215 ÷ 30 = 7.84 L/100 km. The same car shown in UK figures would be about 36 mpg, because the imperial gallon is about 20% larger.
The two scales also feel different. Going from 10 to 20 mpg saves far more fuel than going from 40 to 50 mpg, because consumption is the reciprocal of economy. Liters per 100 km shows those savings directly: 23.5 drops to 11.8 in the first case, but only 5.9 drops to 4.7 in the second.
To turn either figure into money for a trip, enter it in the fuel cost calculator.
Frequently asked questions
How many liters are in a gallon?
A US gallon is exactly 3.785411784 liters. A UK imperial gallon is exactly 4.54609 liters.
How many gallons is 1 liter?
About 0.264 US gallons, or 0.220 UK gallons.
Is 4 liters more than a gallon?
Yes, 4 liters is about 1.057 US gallons, a bit more than one. It’s less than one imperial gallon, though.
How many fluid ounces are in a liter?
About 33.8 US fluid ounces, or 35.2 UK fluid ounces.
Which gallon does the US use for gas?
The US gallon of 3.785 liters. Canada and the UK sell fuel by the liter today, but older UK sources quote imperial gallons and MPG.
Sources and further reading
Related tools
Last reviewed: October 2026