Understand the relationship
Visual explanation
US customary and metric volume units do not line up in whole-number steps. The accurate factor is 3.785411784, although everyday estimates often use 3.785 or 3.8.
Keep enough decimal places for the job. A classroom estimate may use 3.8 L per gallon; technical work should retain the verified factor and round only the final result.
Calculate it
The formula
liters = US gallons × 3.785411784Instant converter
Convert while you learn
1 US gallon equals
liters
Calculated from the canonical unit dataset.
1 × 3785.411784 mL ÷ 1000 mL
Follow the reasoning
Worked examples
Convert 2 US gallons to liters.
2 × 3.785411784 = 7.5708235682 US gal = 7.570823568 L
Convert 5 US gallons to liters.
5 × 3.785411784 = 18.927058925 US gal = 18.92705892 L
Estimate ½ US gallon in liters.
0.5 × 3.785411784 = 1.892705892½ US gal ≈ 1.893 L
Quick lookup
US gallon to liters chart
| US gallons | liters |
|---|---|
| 0.25 | 0.946352946 |
| 0.5 | 1.892705892 |
| 1 | 3.785411784 |
| 2 | 7.570823568 |
| 3 | 11.356235352 |
| 5 | 18.92705892 |
| 10 | 37.85411784 |
Values are generated from the same canonical constants used by the converter. Decimal display may be rounded.
Common mistake
Check the unit and direction
Do not use the Imperial-gallon factor of 4.54609 L. A bare “gallon” is ambiguous internationally; confirm the system before calculating.
Remember it
For a quick reasonableness check, one US gallon is a little less than four liters.
Quick practice
About how many liters are in 7 US gallons?
26.497882488 L, or about 26.50 L.
Accuracy note: Core U.S. liquid relationships and the 231-cubic-inch gallon were checked against NIST Handbook 44 (2026), Appendix C. SI definitions were checked against NIST SI Units—Volume. Imperial values were checked against the UK Weights and Measures Act 1985. Values were last checked on . Review the source list.