US Gallons to Liters Converter
Convert a US pump, paint-can or water-heater volume written in gallons into litres for a metric label or European data sheet.
Updated
How to use
- Enter US liquid gallons from a pump receipt, paint tin or tank plate.
- Read litres. One US gallon is 3.7854 L; five gallons is 18.9271 L.
- Confirm the source is a US gallon. An Imperial gallon is 4.54609 L.
- MPG figures need the fuel-economy tools, not a raw gallon-to-litre swap of the car’s tank.
How it works
US filling stations, paint brands and many appliance plates still use the US liquid gallon. Metric manuals want litres. This page multiplies US gallons by 3.785411784. A 15 gallon fuel tank is 56.7812 L. A 2.5 gallon paint pail is 9.4635 L. A 40 gallon water heater is 151.4165 L.
Pump receipts in the US show gallons. If you are comparing a trip to a European car that reports litres used, convert the gallons first, then compare. Do not treat “10 gallons” as 10 × 4.5 L — that Imperial habit overstates the fuel by about 20%.
Garden sprayers and outdoor tanks sold as “2 gallon” or “5 gallon” become 7.5708 L and 18.9271 L. Mixing instructions written per litre need that conversion before you dilute.
A gallon of water has a mass of about 3.785 kg at typical density. This tool still reports volume only. Hot water, brine and fuel have different densities.
The US dry gallon (used historically for produce) is a different unit and is not used here. Milk sold as a US gallon is the liquid gallon on this page.
Formula
litres = US gallons × 3.785411784
Worked examples
One US gallon at the pump
1 US gal → 3.7854 L
A 5 gallon paint bucket
5 US gal → 18.9271 L
A 15 gallon fuel tank
15 US gal → 56.7812 L
US gallons to litres
| US gal | Litres |
|---|---|
| 1 | 3.7854 |
| 5 | 18.9271 |
| 10 | 37.8541 |
| 15 | 56.7812 |
Useful notes
- US liquid gallon only. Imperial gallons are larger.
- A litre of water is about 1 kg; this page does not convert mass.
- Locked lookup values use the same 3.785411784 factor as the calculator.
FAQ
- How many litres are in a US gallon?
Exactly 3.785411784 litres.
- How many litres in an Imperial gallon?
4.54609 litres — not what this converter uses. Pick US vs Imperial on the MPG tools instead.
- Is a gallon of water 3.785 kg?
A litre of water is about 1 kg, so a US gallon of water is about 3.785 kg at typical density. This tool converts volume, not mass.
- How many litres is a 20 gallon aquarium?
20 × 3.785411784 = 75.7082 L.
- Can I convert a UK gallon here?
No. Multiply Imperial gallons by 4.54609, or convert that litre result on the other volume pages after you have litres.
Related tools
See all Conversions tools.