Gallons to Liters Converter
Type a volume in US gallons into the left box and the liters equivalent appears instantly on the right, using the exact factor of 3.785411784 liters per gallon. Both boxes are live and linked, so editing liters converts straight back to gallons, and a reference table below lists common amounts from 1 to 100. Everything runs in your browser.
How to convert gallons to liters
- Type the volume in US gallons into the left Gallons (gal) box.
- Read the converted value in the right Liters (L) box as it updates live.
- Edit the Liters box instead to convert the other way, back to gallons.
- Check the reference table underneath for 1, 2, 5, 10, 25, 50, and 100 gallons at a glance.
Examples
One gallon
1 gal
3.785412 L
Car fuel tank
15 gal
56.781177 L
Reference-table row
5 gal
18.927059 L
Frequently asked questions
How many liters are in a US gallon?
One US gallon equals exactly 3.785411784 liters. The tool shows this rounded to 3.785412 in the box, and the reference table lists it as the first row.
What is the formula to convert gallons to liters?
Multiply the number of US gallons by 3.785411784. For example, 15 gallons is 15 times 3.785411784, which rounds to 56.781177 liters on screen.
What is the difference between a US gallon and an imperial gallon?
A US gallon is about 3.785 liters, while an imperial (UK) gallon is about 4.546 liters, roughly 20 percent larger. This converter uses US gallons, so switch to the imperial figure if your source is UK based.
Does it convert liters back to gallons too?
Yes. Type into the right Liters box and the left box shows the gallons, using the same factor in reverse. One liter is about 0.264172 US gallons.
How precise are the results?
The underlying math is exact, since a US gallon is defined as 3.785411784 liters. Displayed values are rounded to six decimal places, so 5 gallons reads as 18.927059 rather than a longer string of digits.
How do I convert a fuel tank size from gallons to liters?
Multiply the tank's gallon capacity by 3.785411784. A 12 gallon tank holds about 45.42 liters, and a 20 gallon tank holds about 75.71 liters.
Does this handle US dry gallons or fluid gallons?
It uses the US liquid (fluid) gallon of 3.785411784 liters, the one used for fuel, milk, and paint. The rarely used US dry gallon is larger, about 4.405 liters, and is not covered here.
Can I convert decimals or very large volumes?
Yes. Any finite number works, including decimals like 2.5 gallons and large tank or pool volumes. Non-numeric entries simply clear the opposite box until you type a valid number.
Is my data sent anywhere?
No. The conversion runs entirely in your browser, so the volumes you type never leave your device.
Learn more
- US gallon vs imperial gallon: why the numbers differ
The US and UK gallon are not the same size. Here is where each definition came from and how to avoid mixing them up in a conversion.
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