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Gallons (US) measure larger liquid volumes in the imperial system; litres in the metric one. Fuel, water use and container sizes cross between them, so this converter turns US gallons into litres and back.
How is it calculated?
The conversion factor
1 US gallon = 3.785412 litres.
| To convert | Do this |
|---|---|
| gal → L | multiply by 3.785412 |
| L → gal | divide by 3.785412 |
This is the US gallon. The UK (imperial) gallon is larger at 4.546 litres.
Common values
| US gallons | Litres |
|---|---|
| 1 gal | 3.79 L |
| 5 gal | 18.93 L |
| 10 gal | 37.85 L |
| 15 gal | 56.78 L |
Worked example
A 15-gallon fuel tank holds 15 × 3.785412 = 56.8 litres. A 5-gallon water bottle is 18.9 L. To go back, 40 L of fuel is 40 ÷ 3.785412 = 10.57 US gallons.
FAQ
How many litres is 1 US gallon?+
One US gallon is 3.785412 litres. Multiply gallons by 3.785412 to get litres.
How do I convert gallons to litres?+
Multiply the gallon value by 3.785412. For example, a 20-gallon tank is 20 × 3.785412 = 75.7 L.
Is this a US or UK gallon?+
This uses the US gallon (3.785 L). The imperial (UK) gallon is noticeably larger at 4.546 litres — about 20% more — so the distinction matters for fuel economy figures.
How do I convert litres back to gallons?+
Divide the litre value by 3.785412. So 50 L is 50 ÷ 3.785412 = 13.2 US gallons.
How many litres in 5 gallons?+
5 US gallons is 18.93 litres — the size of a typical large water-cooler bottle.