US gallons to litres converter
1 gal = 3.785411784 L. Type a value in either box — the other side updates instantly, using the exact definition factor, not a rounded shortcut. One US gallon is exactly 3.785411784 litres. Beware the imperial gallon used historically in the UK — it is about 20% larger.
Rate: 1 gal = 3.785411784 L · 1 L = 0.2641720524 gal
Formula and a worked example
litres = US gallons × 3.785411784. Worked example: 10 gal × 3.785411784 = 37.854118 L. To go back, divide by the same factor (or multiply by 0.2641720524).
Where the factor comes from: The US gallon is defined as exactly 231 cubic inches, which works out to 3.785411784 litres. Factors on UnitPairs follow the NIST definitions, so results agree between pages to the last digit shown.
US gallons to litres chart
| US gallons (gal) | litres (L) |
|---|---|
| 1 | 3.785412 |
| 2 | 7.570824 |
| 5 | 18.927059 |
| 10 | 37.854118 |
| 15 | 56.781177 |
| 20 | 75.708236 |
| 50 | 189.270589 |
Questions
How many litres are in one US gallon?
Exactly 3.785411784 L — that is the rate this converter applies in both directions.
How do I convert gal to L by hand?
Multiply the US gallons value by 3.785411784. For a rough mental estimate, 3.785 is usually close enough — but use the full factor for anything you plan to build, buy or dose.
How accurate is this converter?
The factors are the exact international definitions, so the only rounding is in the display — results are shown to six decimal places, and the underlying value is never pre-rounded.
Related conversions
- litres to US gallons — the reverse of this page
- litres to US gallons
- millilitres to US fluid ounces
- Height converter — centimetres to feet and inches
- Full conversion chart — every pair on one page