This free converter changes US gallons (gal) into litres (L) and back again, updating live as you type. It’s handy for fuel volumes, recipe scaling, and reading container sizes when switching between US and metric measurements.
How it works
The US liquid gallon is defined as exactly 231 cubic inches, which equals 3.785411784 litres. The converter applies that single fixed factor:
litres = US gallons × 3.785411784 (and gallons = litres ÷ 3.785411784)
Type in the gallons field to multiply, or the litres field to divide. Note this is the US gallon — the UK imperial gallon is a different, larger unit (4.546 L).
Example
You fill a tank with 12 US gallons of fuel and want the metric figure:
12 × 3.785411784 = 45.42 litres
So 12 US gallons is just over 45 litres.
| US Gallons (gal) | Litres (L) |
|---|---|
| 1 gal | 3.7854 L |
| 5 gal | 18.9271 L |
| 10 gal | 37.8541 L |
| 100 gal | 378.5412 L |
All calculations run entirely in your browser — no data is sent to any server.