Convert GALLONS to LITERS, Free
Type any GALLONS value and see the LITERS result instantly. No button press needed.
How to convert GALLONS to LITERS
There are two different gallon measurements in common use, and they are not the same: the US liquid gallon is 3.78541 liters, while the Imperial gallon used in the UK and Canada is 4.54609 liters. That is a 20 percent difference, which matters when comparing fuel efficiency between American and British cars, reading international recipes, or buying liquid chemicals across borders. This converter uses the US gallon by default, with an option to switch to Imperial.
The calculation is a direct multiplication: liters = gallons x 3.78541 (US) or gallons x 4.54609 (Imperial). The converter applies the full precise factor with no rounding in the intermediate step, running instantly in your browser with no data sent anywhere.
Select US or Imperial gallon
Choose which gallon system you are working with. US gallons are used in the United States and Liberia. Imperial gallons are used in the UK, Canada, and some Caribbean countries.
Enter the gallon value
Type the number of gallons to convert. Decimals are accepted; for example, 2.5 gallons converts to 9.464 liters (US) or 11.365 liters (Imperial).
Read the liter result
The equivalent in liters appears immediately. The formula is: liters = gallons x 3.78541 for US, or gallons x 4.54609 for Imperial.
Convert in the other direction if needed
To convert liters to gallons, use the reverse converter or divide by the same factor: 3.78541 for US gallons or 4.54609 for Imperial gallons.
Frequently asked questions
Why does a British car get better fuel economy in liters per 100 km than American MPG suggests?
This is partly the gallon difference. A UK car rated at 40 mpg uses Imperial gallons, so it actually uses 4.546 liters per gallon traveled, not 3.785. When converted to the same unit (liters per 100 km), the UK rating works out to about 7.1 L/100km, while a US car at 40 mpg works out to about 5.88 L/100km. The UK car is actually more efficient than the same mpg figure in the US.
How many liters are in a US gallon exactly?
Exactly 3.785411784 liters. This value was defined by international agreement in 1959. For practical purposes, 3.785 is accurate enough for most calculations.
Is this the same conversion used for gas pumps outside the US?
Gas pumps in countries using the metric system sell fuel in liters. If you fill up in Europe and want to know how many US gallons you bought, divide the liter amount by 3.785.
How does a gallon compare to a quart or a pint?
One US gallon equals 4 quarts, 8 pints, or 16 cups. These are fixed US liquid measure relationships. The Imperial system uses the same names for the subdivisions but the base gallon is larger.