The exact equivalent
A US gallon is 3.78541 litres, so a litre is 0.264172 US gallons. The imperial gallon is a different, larger unit at 4.54609 litres.
1 l = 0.26417205 gal
1 gal = 3.78541178 l
How to convert it by hand
Just multiply by the conversion factor. To go from litres to US gallons, multiply by 0.264172; to come back, divide by that same number or multiply by 3.785412.
For example: 25 l × 0.264172 = 6.6043 gal.
A tip that saves mistakes: check the result goes the way you expect. If US gallons are a smaller unit than litres, the number has to come out bigger. If it comes out smaller, you divided when you should have multiplied.
Conversion table
| l | gal |
|---|---|
| 1 | 0.2642 |
| 2 | 0.5283 |
| 5 | 1.3209 |
| 10 | 2.6417 |
| 20 | 5.2834 |
| 50 | 13.2086 |
| 100 | 26.4172 |
Reference points to picture it
| Reference | Equals |
|---|---|
| A car fuel tank | 50 l = 13.2 gal |
| A large bottle of water | 1.5 l = 0.40 gal |
| A bathtub | 150 l = 39.6 gal |
| A US gallon | 3.79 l |
The trick for doing it in your head
Divide by 4 and add about 6%. For 50 litres: 50 ÷ 4 = 12.5, plus a bit, gives 13.2 gallons.
It is fine for getting by without a phone, but not for anything that depends on precision: in a recipe, on a building site or in a dose, use the exact conversion.