To convert US gallons to liters, multiply by 3.785411784. 1 gallon is 3.785 L, 5 gallons is 18.93 L, and a 50-gallon water heater holds 189.3 L.
Gas, milk, paint and aquariums are sold by the gallon in the US. Use this page to compare prices, tank sizes or product specs with metric countries.
How to use the gallons to liters converter
- Type the value in gallons into the box. Decimals are fine.
- The result in liters updates as you type, along with the working.
- Need the other way? Switch the direction menu, or open the liters to gallons converter.
Formula
A US gallon is defined as 231 cubic inches, which is exactly 3.785411784 liters. The UK imperial gallon is a different unit: exactly 4.54609 L, about 20% larger.
Worked example
A car has a 13-gallon fuel tank. How many liters is that?
- 13 × 3.785411784 = 49.21.
- Result: 49.2 L.
Price example: gas at $3.50 per gallon is $3.50 ÷ 3.785 = $0.92 per liter. For trip costs, use the fuel cost calculator (gas trip cost).
Gallons to liters chart
Common values, rounded to 3 decimal places.
| Gallons (gal) | Liters (L) |
|---|---|
| 0.25 gal | 0.946 L |
| 0.5 gal | 1.893 L |
| 1 gal | 3.785 L |
| 2 gal | 7.571 L |
| 3 gal | 11.356 L |
| 5 gal | 18.927 L |
| 10 gal | 37.854 L |
| 12 gal | 45.425 L |
| 13 gal | 49.21 L |
| 15 gal | 56.781 L |
| 20 gal | 75.708 L |
| 25 gal | 94.635 L |
| 30 gal | 113.562 L |
| 40 gal | 151.416 L |
| 50 gal | 189.271 L |
| 55 gal | 208.198 L |
| 75 gal | 283.906 L |
| 100 gal | 378.541 L |
| 1,000 gal | 3,785.412 L |
US vs imperial gallons
Canada and the UK sell fuel in liters, but older British and Canadian sources (and UK car mpg figures) use the imperial gallon, 4.546 L. A UK "gallon" of fuel is 1.2 US gallons, which is why UK mpg numbers look higher than US ones for the same car.
- Milk jug: 1 US gal = 3.79 L.
- Aquarium: a 55-gallon tank is 208.2 L.
- Paint: a 5-gallon bucket is 18.9 L.
Quick mental math
Multiply by 4 and take off 5%. 10 gal × 4 = 40, minus 2 = 38 L (exact: 37.85).
Related conversions
Going the other way: liters to gallons converter. Related pages: . For other units in the same family, use the full volume converter.
Caveats and assumptions
- Uses US gallons. For imperial (UK) gallons, multiply liters by 0.219969 instead.
- Results show up to 10 significant digits; the chart is rounded for reading. Keep full precision for engineering, medical or legal work.
Frequently asked questions
How many liters are in a gallon?
3.785 L in a US gallon; 4.546 L in an imperial gallon.
How many liters is 5 gallons?
18.93 liters (US).
How do I convert price per gallon to price per liter?
Divide the price by 3.785. $4.00/gal = $1.057/L.
Why is the UK gallon bigger?
The imperial gallon (1824) was based on 10 lb of water; the US kept the older 231 cubic-inch wine gallon.
Sources
- NIST — SI Units: Volume — liter, US gallon and fluid ounce
- NIST SP 811 Appendix B.9 — Conversion factors — gallon (US) and gallon (UK) to liter
- UK Weights and Measures Act 1985, Schedule 1 — defines the stone (14 lb), imperial gallon and imperial fluid ounce
This calculator gives estimates for planning and education. Check measurements, local codes, supplier specs and your school's official policy before relying on a result. See our disclaimer and how we build and check calculators.