Gallons to Liters
Convert US gallons to liters in your browser, with a warning about the UK gallon, which is a fifth larger.
l = gal × 3.785411784
NIST SP 811 (2008), Appendix B.8 — gallon (US liquid) (gal) to cubic meter (m³) = 3.785 412 E−03
Fuel, paint, tanks and recipes all get quoted in gallons somewhere. The catch is that there are two of them: the US gallon of 3.785411784 liters and the UK gallon of 4.54609 liters. This page converts the US one, which is the one meant unless the context is explicitly British.
How it is calculated
l = gal × 3.785411784
The US gallon is defined as 231 cubic inches exactly, and since the inch is exactly 25.4 millimeters, the conversion to liters is exact too. The UK gallon has an entirely separate history and is about 20 % larger.
Source: NIST SP 811 (2008), Appendix B.8 — gallon (US liquid) (gal) to cubic meter (m³) = 3.785 412 E−03
Common values
| US gallons | liters |
|---|---|
| 1 | 3.785412 |
| 2 | 7.570824 |
| 5 | 18.92706 |
| 10 | 37.85412 |
| 12 | 45.424944 |
| 15 | 56.78118 |
| 20 | 75.70824 |
| 25 | 94.6353 |
| 30 | 113.56236 |
| 50 | 189.2706 |
| 100 | 378.5412 |
Questions people ask
- Which gallon am I looking at?
- If the source is American, it is the US gallon. If it is British or from an older Commonwealth document, it is the imperial gallon and about a fifth larger. Fuel economy figures are where this bites hardest: the same car appears to do noticeably better on imperial gallons.
- Why 231 cubic inches?
- It is inherited. The US gallon comes from the English wine gallon, which was defined by the size of a cylinder rather than by anything metric. The number survived the definition changing underneath it, which is why it looks so arbitrary today.
- How much does a gallon of water weigh?
- A US gallon of water is 3.785411784 liters, and a liter of water is close to a kilogram, so it comes to about 3.79 kilograms or 8.34 pounds. The exact figure moves slightly with temperature.
Found a problem, or want more?
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