Gallons to Litres Converter
Convert US gallons to litres — multiply by 3.785. Results update as you type; exact factors shown.
One US gallon is 3.7854 litres — see the exact factor, not a rounded rule of thumb.
How the gallons to litres converter works
Volumes convert through the litre (exactly 1 dm³). The US gallon is exactly 3.785411784 L (231 cubic inches); the imperial gallon is exactly 4.54609 L. A US fluid ounce is 29.5735 mL, an imperial fluid ounce 28.4131 mL; a US pint is 16 US fl oz, an imperial pint 20 imperial fl oz.
Australia is fully metric under the National Measurement Act 1960; imperial units appear only in trade with the US and in older documents.
Common volume conversions
| From | To | Units |
|---|---|---|
| 1 US gal | 3.7854 L | US gallon to litres |
| 2 US gal | 7.5708 L | US gallons to litres |
| 3 US gal | 11.3562 L | US gallons to litres |
| 5 US gal | 18.9271 L | US gallons to litres |
| 10 US gal | 37.8541 L | US gallons to litres |
| 12 US gal | 45.4249 L | US gallons to litres |
| 15 US gal | 56.7812 L | US gallons to litres |
| 20 US gal | 75.7082 L | US gallons to litres |
| 25 US gal | 94.6353 L | US gallons to litres |
| 50 US gal | 189.2706 L | US gallons to litres |
| 100 US gal | 378.5412 L | US gallons to litres |
| 250 US gal | 946.3529 L | US gallons to litres |
Units in this converter and their exact factors
| Unit | Symbol | One unit in litres |
|---|---|---|
| millilitre | mL | 0.001 litre |
| litre | L | 1 litre |
| cubic metre | m³ | 1,000 litre |
| teaspoon (metric) | tsp | 0.005 litre |
| tablespoon (metric) | tbsp | 0.015 litre |
| cup (metric) | cup | 0.25 litre |
| US fluid ounce | US fl oz | 0.0295735296 litre |
| US cup | US cup | 0.2365882365 litre |
| US pint | US pt | 0.473176473 litre |
| US gallon | US gal | 3.785411784 litre |
| imperial fluid ounce | imp fl oz | 0.0284130625 litre |
| imperial pint | imp pt | 0.56826125 litre |
| imperial gallon | imp gal | 4.54609 litre |
| cubic foot | ft³ | 28.316846592 litre |
FAQFrequently asked questions about volume conversion
How many litres is 1 US gallon?
3.78541 litres.
What is 15 gallons in litres?
56.8 litres.
Is this the imperial gallon?
No, this page uses the US gallon. The imperial gallon is 4.54609 litres.
How many litres in a US pint?
0.473 litres — under half a litre, unlike the UK pint at 0.568.
Why does fuel economy not convert directly?
Because miles per gallon and litres per 100 km are inverses of each other; use the fuel economy converter.
Where these figures come from
- BIPM — The International System of Units (SI Brochure, 9th edition) — definitions of the base and derived units.
- NIST Special Publication 811 — Guide for the Use of the International System of Units — the exact conversion factors used here.
- National Measurement Institute (NMI) — Australia's national measurement authority.
Last checked: September 2026. Conversion factors are fixed by definition and do not change with tax years or regulations.