Gallons to Liters Converter Tool

Which gallon this uses

This converter uses the US liquid gallon (3.78541 liters), the standard in US fuel pumps, recipes, and paint cans. It is not the UK imperial gallon (4.54609 liters) — using this tool for a UK-sourced figure will be off by about 20%, so check which gallon your source number is actually in before converting.

Worked example

A standard US gas tank fill of 12 gallons: 12 × 3.78541 = 45.42492, which the tool rounds to 45.42 liters. For a smaller amount — a 1-gallon paint can — 1 × 3.78541 = 3.79 liters.

Where the factor comes from

3.78541 liters is the volume of 231 cubic inches, which is how the US liquid gallon has been legally defined since 1893 (the Mendenhall Order tied US units to the metric system). It's not a round number in either system because the gallon and liter were standardized independently, centuries apart.