How to use it
- Enter the volume.
- Choose US gallon or UK gallon as the From unit.
- Read the result in liters.
- Check the other units shown below.
The formula
- 1 US gallon = 3.785411784 L, so liters = US gallons × 3.785
- 1 UK gallon = 4.54609 L, so liters = UK gallons × 4.546
- 1 L = 0.264 US gallons
Both gallon definitions are exact. The UK gallon is about 20% bigger, which is why it matters which one a source means. US recipes, gas pumps and car specs always use the US gallon.
Example: a 16-gallon gas tank holds 16 × 3.785 = 60.6 liters. A 2-liter soda bottle is 2 × 0.264 = 0.53 US gallons, just over half a gallon.
US gallons to liters chart
| US gallons | Liters |
|---|---|
| 1 gal | 3.79 L |
| 2 gal | 7.57 L |
| 5 gal | 18.93 L |
| 10 gal | 37.85 L |
| 15 gal | 56.78 L |
| 20 gal | 75.71 L |
| 50 gal | 189.3 L |
| 55 gal (drum) | 208.2 L |
And the smaller US units: 1 quart = 0.946 L, 1 pint = 473 mL, 1 cup = 237 mL, 1 fl oz = 29.57 mL.
Gas prices and fuel economy
To compare US gas prices with prices abroad, divide the price per gallon by 3.785. $3.50 per gallon is about $0.92 per liter. Going the other way, a price per liter times 3.785 gives the price per US gallon.
Fuel economy is trickier because most countries use liters per 100 km, where lower is better. To convert: L/100 km = 235.215 ÷ mpg (US). So 25 mpg is 9.4 L/100 km and 40 mpg is 5.9 L/100 km. A car rated in UK mpg looks more efficient because the UK gallon is larger: 40 UK mpg is about 33 US mpg.
US units of liquid volume
| Unit | Equals | Milliliters |
|---|---|---|
| 1 gallon | 4 quarts | 3,785 |
| 1 quart | 2 pints | 946 |
| 1 pint | 2 cups | 473 |
| 1 cup | 8 fl oz | 237 |
| 1 fl oz | 2 tbsp | 29.6 |
The UK system uses the same names with different sizes: an imperial pint is 568 mL (20 imperial fl oz), which is why a British pint of beer is noticeably larger than an American one.
Everyday uses
- Aquariums are sold by US gallons; a 20-gallon tank holds about 76 L.
- Water heaters: a 50-gallon tank is 189 L.
- Paint: a US gallon covers roughly 350 to 400 sq ft per coat according to many manufacturers; European paint is sold in liters.
- Drinking water: health advice abroad often uses liters; 2 L a day is just over half a gallon.
For kitchen measures like cups and tablespoons, the cups to grams converter is more convenient. All calculations run in your browser.
Frequently asked questions
How many liters are in a gallon?
A US gallon is 3.785 liters. A UK (imperial) gallon is 4.546 liters.
How many gallons is 1 liter?
1 liter is 0.264 US gallons, or about a quarter of a gallon.
How many liters is 5 gallons?
5 US gallons is 18.93 liters.
Is a gallon of water 8 pounds?
Close: a US gallon of water weighs about 8.34 lb (3.78 kg) at room temperature.
Which gallon does my car's tank use?
In the US, always the US gallon. In the UK, fuel is sold by the liter, but some people still quote fuel economy in imperial mpg.
Last updated: November 12, 2026