How Many Liters in a Gallon
A liters-in-a-gallon page converts liquid volume between metric liters and customary/imperial gallons. A US liquid gallon equals approximately 3.7854 liters. An Imperial (UK) gallon equals exactly 4.54609 liters. The page assists with vehicle fuel economy conversions, water tracking, and commercial shipping volumes.
Convert between gallons and liters instantly. Learn the key differences between the US liquid gallon and the Imperial volume standard.
Quick Answer
Find out how many liters are in a gallon (3.785 liters per US gallon, and 4.546 liters per Imperial gallon).
How Many Liters Are in a Gallon?
There are 3.7854 liters in a US Customary liquid gallon.
An Imperial (UK) gallon is larger, containing exactly 4.5461 liters.
Gallon Standard Type
Formula: 1 Gallon = 3.7854 liters (US Liquid Gallon (1 gal = 3.785 L))
Gallons to Liters Conversion Table
| Gallons (gal) | US Liters (L) | Imperial Liters (L) |
|---|---|---|
| 1 gal | 3.79 L | 4.55 L |
| 2 gal | 7.57 L | 9.09 L |
| 5 gal (Common Jug) | 18.93 L | 22.73 L |
| 10 gal | 37.85 L | 45.46 L |
| 20 gal | 75.71 L | 90.92 L |
| 50 gal (Common Barrel) | 189.27 L | 227.30 L |
Examples
1 Gallon (US)
3.785 L
1 Gallon (Imperial)
4.546 L
5 Gallons (US)
18.927 L
How it works
To convert between the metric volume system (liters) and the traditional imperial system (gallons), we apply standard conversion factors:
US Gallon to Liters
1 Gallon = 3.7854 Liters
Imperial Gallon to Liters
1 Gallon = 4.5461 Liters
US Conversion Formula
Multiply US gallons by 3.78541 to get liters. Divide liters by 3.78541 to get US gallons.
US vs. Imperial Gallons
The term "gallon" is shared by two distinct measurement standards, which can cause confusion in shipping, aviation, and recipe execution:
- US Liquid Gallon: The standard unit used in the United States, equal to 231 cubic inches or approximately 3.785 liters.
- Imperial Gallon: The standard unit historically used in the United Kingdom, Canada, and other Commonwealth countries, equal to approximately 4.546 liters. It is roughly 20% larger than the US liquid gallon.
For example, fuel economy figures (Miles Per Gallon) are significantly different depending on whether US gallons or Imperial gallons are referenced.
Common Practical Applications
Liquid conversions between metric and customary units are extremely common in daily life:
- Drinking Water: A common health goal is to drink a gallon of water per day. Using standard 1-liter reusable bottles, this equates to drinking slightly under 4 full bottles (approx. 3.78 bottles).
- Aquariums: Fish tanks are sold under gallon ratings. Calculating exact water volume in liters is critical for correctly calculating chemical doses and medications.
- Automotive Fluids: Engine coolants and windshield wash are frequently distributed in 1-gallon or 4-liter containers.
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