Convert Gallon (US) to Liter
Conversion Formula
L = gal × 3.78541To convert Gallon (US) to Liter, use the formula above. This is the standard conversion factor used worldwide.
Conversion Table
| Gallon (US) (gal) | Liter (L) |
|---|---|
| 1 | 3.785410 |
| 5 | 18.927050 |
| 10 | 37.854100 |
| 20 | 75.708200 |
Why convert Gallon (US) to Liter
A US car's fuel tank capacity, a paint can's volume, or a household water usage figure given in gallons needs converting to liters when comparing against a product spec or utility bill from outside the US. It runs opposite to the more common liter to gallon lookup, usually starting from a number on a US label rather than curiosity about a metric figure.
Where the number comes from
This page converts from the US liquid gallon, exactly 3.785411784 liters, not the larger imperial gallon (4.54609 L) still used in the UK. Multiplying a US gallon figure by 3.785411784 gives an exact liter result, and the two gallons are close in name but different enough in size that using the wrong one changes a result by roughly a fifth.
Quick reference
| 1 US gal | 3.7854 L | exact ratio 3.785411784 |
| 12 US gal | 45.42 L | a common midsize car fuel tank |
| 1 imperial gal | 4.54609 L | UK gallon, larger than the US gallon |
| 5 US gal | 18.93 L | a common bucket or water jug size |
| 55 US gal | 208.2 L | a standard oil drum |
| 1 US qt (1/4 gal) | 0.9464 L |
Common mistakes
- Converting a US gallon figure with the imperial gallon's factor by mistake, easy to do since both show up on generic 'liters per gallon' calculators online, understates the true liter volume by about 17 percent.
- Fuel economy comparisons have the reverse trap: converting a US mpg figure directly against a European L/100km rating, without inverting for the fact that one measures distance per volume and the other volume per distance, produces a number that isn't actually comparable.
Frequently Asked Questions
How many liters are in a typical US car fuel tank?
A common 12 to 15 gallon tank holds roughly 45 to 57 liters, useful to know before renting a car abroad where the pump and dashboard both read in liters.
Why does converting my gallon figure with an online calculator sometimes give a different answer?
Some calculators default to the imperial gallon instead of the US gallon, a roughly 20 percent difference. Check which gallon a tool assumes before trusting the result for anything precise.
How do I convert US mpg to a European L/100km rating?
Divide 235.21 by your mpg figure. The formula inverts because mpg measures distance per volume while L/100km measures volume per fixed distance, so a simple unit multiplication will not work.
Is a US gallon of paint the same volume as a UK gallon of paint sold under the same name?
No. A US gallon can, 3.785 L, holds meaningfully less than a UK imperial gallon can, 4.546 L, would, which matters when estimating coverage from a US-labeled product spec against a UK job.