Direct answer
How Many Liters in a US Gallon? 1 gal ≈ 3.78541 L
1 US liquid gallon equals about 3.78541 liters. Quick fuel and liquid answer with formula and gallon ↔ liter converters.
Question
How many liters are in a US gallon?
1 US liquid gallon equals approximately 3.78541 liters.
1 US gal
≈ 3.78541 L
5 US gal
≈ 18.927 L
Formula
liters = US gallons × 3.78541
Explanation
US fuel pumps, milk jugs, and many product labels use the US liquid gallon.
Multiply US gallons by 3.78541 to get liters. Divide liters by 3.78541 to get US gallons.
Example: 10 US gal ≈ 37.854 L; 50 L ≈ 13.209 US gal.
Important caveat
The UK (imperial) gallon is larger: about 4.54609 L. This answer is for the US liquid gallon only.