How to convert cubic feet to gallons (US)
- Take the value in cubic feet.
- Use the formula gallons (US) = cubic feet × 7.480519481.
- For example, 1 ft³ is 7.48 gal.
About cubic feet and gallons
A cubic foot is 1,728 cubic inches and a US gallon is defined as 231 cubic inches, so 1 cubic foot is 1,728 ÷ 231 = 7.48052 gallons. Multiply cubic feet by 7.48 to get US gallons. For a rough answer multiply by 7.5.
You meet this when working out how much water a pool, pond, tank or hot tub holds from its dimensions in feet, reading a US water bill, or sizing soil and mulch for a garden bed.
Examples
- 1 ft³ (one cubic foot) is 7.48 gal
- 2 ft³ (a common bag of mulch) is 14.96 gal
- 32 ft³ (a 4 by 8 ft raised bed filled 1 ft deep) is 239.38 gal
- 100 ft³ (one CCF billing unit on a US water bill) is 748.05 gal
Cubic feet to gallons chart
| Cubic feet (ft³) | Gallons (US) |
|---|---|
| 0.5 | 3.74 |
| 1 | 7.48 |
| 2 | 14.96 |
| 3 | 22.44 |
| 4 | 29.92 |
| 5 | 37.4 |
| 6 | 44.88 |
| 7 | 52.36 |
| 8 | 59.84 |
| 9 | 67.32 |
| 10 | 74.81 |
| 12 | 89.77 |
| Cubic feet (ft³) | Gallons (US) |
|---|---|
| 15 | 112.21 |
| 20 | 149.61 |
| 25 | 187.01 |
| 30 | 224.42 |
| 40 | 299.22 |
| 50 | 374.03 |
| 75 | 561.04 |
| 100 | 748.05 |
| 200 | 1,496.1 |
| 500 | 3,740.26 |
| 1,000 | 7,480.52 |