Gallons to Liters
Result:
Enter a volume to convert.
Convert U.S. gallons to liters. From is set to gallons and To is set to liters. The result updates as you type. One U.S. gallon is exactly 3.785411784 liters. Other units are on the volume converter. The other direction is liters to gallons.
Gallons to liters formula
NIST Handbook 44 (2024), Appendix C defines the U.S. gallon as 231 cubic inches. With the exact inch of 2.54 cm, that gallon is 3.785411784 liters. This page does not use the imperial gallon.
Formula: liters = gallons × 3.785411784.
The converter multiplies by that exact gallon, then rounds the displayed result to five decimal places. One gallon shows 3.78541 L, because the next digit is 1.
Example: 5 gal × 3.785411784 = 18.92706 L.
Gallons to liters reference table
Each value below is the converter result at five decimal places, using the U.S. gallon of 3.785411784 liters. Enter the same gallons in the form above and the result should match.
| U.S. gallons | Liters |
|---|---|
| 0.25 | 0.94635 |
| 0.5 | 1.89271 |
| 1 | 3.78541 |
| 2 | 7.57082 |
| 3 | 11.35624 |
| 5 | 18.92706 |
| 10 | 37.85412 |
| 12 | 45.42494 |
| 15 | 56.78118 |
| 20 | 75.70824 |
| 50 | 189.27059 |
| 55 | 208.19765 |
| 100 | 378.54118 |
Gallons to liters examples
Groceries: A 1 gal jug of milk holds 3.78541 L, and a half-gallon carton holds 1.89271 L.
Fuel tank: A 15 gal tank holds 15 × 3.785411784 = 56.78118 L.
Buckets and drums: A 5 gal bucket holds 18.92706 L, and a 55 gal drum holds 208.19765 L.
Quick mental math (approximation)
To estimate liters, multiply the U.S. gallons by 4, then take off 5 percent. That is about the same as multiplying by 3.8. Example: 15 gal × 4 is 60, minus 3 is about 57 L. The exact result is 56.78118 L.
This shortcut is an approximation. Multiplying by 3.8 runs about 0.4 percent high. Multiplying by 4 alone runs about 6 percent high. Use the converter or the exact formula for fuel logs, invoices, or records.
Gallons to liters FAQ
How many liters are in a gallon?
One U.S. gallon is exactly 3.785411784 liters. The converter rounds that to five decimal places and shows 3.78541 L.
How many liters are in a quart?
A U.S. quart is one quarter of a gallon, so it is 3.785411784 ÷ 4 liters. The converter shows 0.25 gal as 0.94635 L.
Does this work for imperial (UK) gallons?
No. The imperial gallon is a larger unit, so it holds more liters than the U.S. gallon. This page uses only the U.S. gallon.