Gallons to Liters
Convert us gallon to liter instantly — type a value and read the result, with the exact formula shown.
Example
1 gal = 3.785412 L, 5 gal = 18.92706 L, 10 gal = 37.85412 L.
How it works
Liter = US gallon × 3.785412. Every value is converted through a single liter base unit using internationally defined conversion factors, so any from/to pair stays consistent.
Good to know
Converting US gallons to liters comes up constantly when you cross between American and metric systems: filling a car at a European petrol station priced per liter, scaling a recipe or a home-brew batch printed in liters, sizing an aquarium or water tank, or buying paint, fuel, and chemicals whose labels switch units by region. Because the US still prices fuel and milk by the gallon while almost everywhere else uses liters, this is one of the most searched volume conversions for travelers and importers.
The gallon is an old imperial-era unit, but the US gallon was fixed to a specific value: exactly 231 cubic inches, which works out to 3.785412 liters. The liter is the metric everyday unit of volume, defined as one cubic decimeter (a 10 cm cube). Watch out for the British connection: the UK and many Commonwealth countries use the imperial gallon, which is larger at about 4.546 liters, so the same word means two different sizes depending on the country.
A handy rule of thumb: a US gallon is just under 3.8 liters, so multiply gallons by 4 and shave off roughly 5% to estimate. Even simpler, four US gallons is almost exactly 15 liters (15.14 L), and a 10-gallon tank holds about 38 liters. For quick mental math, "gallons times 3.8" gets you within a fraction of a liter.
- Common mistake: using the US factor (3.785412) when a label actually means imperial gallons (4.546) will leave you short by about 20%, which matters a lot for fuel economy and tank sizing.
Frequently asked questions
How do you convert us gallon to liter?
Multiply the number of us gallons by 3.785412 to get liters. For example, 1 gal = 3.785412 L.
What is 1 us gallon in liters?
1 us gallon equals 3.785412 liters (1 gal = 3.785412 L).
How many us gallons are in 1 liter?
There are 0.2641721 us gallons in 1 liter.
Is this converter free and private?
Yes. It runs entirely in your browser, so your inputs never leave your device, there is no sign-up, and it works offline once loaded.
Are the conversions exact?
Conversions use internationally defined factors and are exact where the definitions are exact (for example, 1 inch = 2.54 cm). Displayed results are rounded for readability.
People also ask
How many liters are in a US gallon of gas?
A US gallon equals 3.785412 liters, so a typical 15-gallon car tank holds about 56.8 liters. This is the figure to use when comparing US gas prices to per-liter prices abroad.
What is the difference between a US gallon and an imperial gallon in liters?
A US gallon is 3.785412 liters, while a UK (imperial) gallon is about 4.546 liters, roughly 20% larger. Always check which gallon a product or country is referring to before converting.
How do I convert gallons to liters quickly in my head?
Multiply the number of gallons by 3.8 for a close estimate, or by 4 and then subtract about 5%. For example, 5 gallons is roughly 5 x 3.8 = 19 liters (exact value 18.93 L).
How many liters is 5 gallons?
5 US gallons equals 18.92706 liters. This is why a standard 5-gallon water cooler bottle is often labeled as 18.9 liters.
How many liters is a 55 gallon drum?
A 55 US gallon drum holds about 208.2 liters (55 x 3.785412). It is frequently rounded to 208 liters or labeled as a 200-liter drum in metric markets.
Is 1 gallon exactly 4 liters?
No, a US gallon is 3.785412 liters, slightly less than 4. Rounding it to 4 liters overstates the volume by about 5.7%, which can add up over large quantities.
How many gallons is 10 liters?
10 liters equals about 2.64 US gallons (10 x 0.2641721). To go from liters back to US gallons, multiply by 0.2641721 or divide by 3.785412.
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