Use gallons to liters to choose either direction of the US liquid gallon/liter pair. Use liters to gallons for a liter input with several customary volume results.
1 US liquid gallon = 3.785411784 L follows from the 231-cubic-inch gallon and exact inch definition.
| Gallons to liters | Liters to gallons | |
|---|---|---|
| Inputs | Direction and nonnegative amount | Nonnegative liters |
| Primary | L or US gal, exactly 2 decimals | US gal, up to 6 decimals |
| Details | US gallons and liters, up to 9 decimals | Imperial gallons, US quarts, US cups, liters-per-US-gallon factor |
| Example | 12 US gal → 45.42 L | 10 L → 2.641721 US gal; 2.199692 imp gal |
The bidirectional form starts with 1 US gal and returns 3.79 L. Its longer supporting rows and Copy output retain up to 9 decimal places, rather than only the two-place primary display.
For a metric bottle or stated container volume, the liters-first page exposes the US and imperial gallon labels together. They are different units; its imperial row uses approximately 4.54609 L per imperial gallon. Do not feed an imperial gallon amount into the US-only pair.
Limits
Both change volume labels; neither returns weight, working container capacity or a treatment quantity. Keep the original measurement and gallon standard attached. A rounded primary display can lose information even when the underlying factor is defined exactly.
Sources
NIST SP 811, unit definitions and Appendix B factors. The paired calculator controls and rounding described above are their current form behavior. NIST Handbook 44, Appendix C, customary unit relationships.