Formulas
1 ft³ = 7.480519 US gal (liquid)
1 ft³ = 6.228835 UK gal
1 ft³ = 6.427010 US dry gal
1 ft³ = 28.3168466 L
General formula: gallons = ft³ × factor and ft³ = gallons ÷ factor
Which gallon should I pick?
- US gallon (liquid): water, plumbing, pools, US utility bills.
- US gallon (dry): older agricultural/crop references.
- UK/Imperial gallon: UK, some Commonwealth, older engineering texts.
FAQ
1. How many gallons of water in a 2 ft × 2 ft × 2 ft cube?
Its volume is 8 ft³. 8 × 7.480519 ≈ 59.844 gallons (US liquid).
2. Why do some sites show slightly different numbers?
Roundings. Our figures use the NIST exact factors (231 in³ per US gallon, 1 ft = 0.3048 m → 1 ft³ = 0.0283168466 m³).
3. Can I use this for water utility calculations?
Yes—many utilities meter in cubic feet (or CCF = 100 ft³) and customers think in gallons. This tool shows the exact multiplier.
Full original guide (expanded)
Add here long-form explanation for SEO: how to convert ft³ to gallons by hand, how to estimate pool volume, and how to check against the water bill (1 CCF = 748.0519 US gal).