Use cubic feet to gallons for a known volume in ft³. Use gallons to cubic feet for a known US liquid gallon amount.
One cubic foot contains 1728 cubic inches; one US liquid gallon contains 231 cubic inches. The forward factor is 1728/231 and the reverse factor is 231/1728. The repeating decimal 7.48051948051948 is a rounded representation of the ratio.
| Cubic feet to gallons | Gallons to cubic feet | |
|---|---|---|
| Default input | 10 ft³ | 10 US gal |
| Primary display | Up to 4 decimals | Up to 6 decimals |
| Default result | 74.8052 US gal | 1.336806 ft³ |
| Details | Entered ft³, liters, US quarts | Cubic inches, liters, cubic meters, gallons-per-ft³ factor |
| Other precision | Liters and quarts up to 2 decimals | Factor fixed 5 decimals: 7.48052 |
Both forms reject negative or invalid numeric inputs and non-finite derived results. Their displays and Copy text can round otherwise finite values.
Starting with dimensions
For a rectangular interior space, length × width × depth in feet gives cubic feet before conversion. Neither form asks for those dimensions or determines a container’s usable capacity. Wall thickness, contents and an advertised nominal capacity are separate facts.
Limits
These are US liquid gallons, not imperial gallons or a dry-material mass. Mathematical inverse factors do not guarantee an exact roundtrip through rounded displays. Converting gallons to weight requires a density.
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.