Cubic Feet to US Gallons Converter (ft³ to gal)
1 ft³ = 1,728 ÷ 231 ≈ 7.480519 US gal. Convert cubic feet to gallons for pools, tanks, water bills and aquariums, with UK gallons alongside.
US gal = ft³ × 1728 ÷ 231 (≈ 7.48052)
Cubic Foot (ft³): A cubic foot is a cube 1 foot on each side, equal to 1,728 cubic inches or exactly 28.316846592 liters. It is used in the US for room and appliance capacity and gas volumes.
US Gallon (gal): The US liquid gallon is defined as exactly 231 cubic inches, which is 3.785411784 liters. It is the gallon used for gasoline, milk and water in the United States.
| Cubic Foot (ft³) | US Gallon (gal) |
|---|---|
| 1 | 7.48051948052 |
| 5 | 37.4025974026 |
| 10 | 74.8051948052 |
| 25 | 187.012987013 |
| 50 | 374.025974026 |
| 100 | 748.051948052 |
Tanks, ponds and pools are easy to measure in feet, but pumps, chemicals and water heaters are rated in gallons. A cubic foot holds 1,728 cubic inches and a US gallon is defined as 231 of them, so each cubic foot holds 1,728 ÷ 231 ≈ 7.48 US gallons, a ratio fixed by definition rather than by measurement.
US water utilities often bill in CCF, hundreds of cubic feet, so this conversion also turns a meter reading into gallons: one CCF is about 748 gallons. The chart adds UK gallons for readers in Britain, where a cubic foot holds about 6.23 imperial gallons.
How to use this tool
- Type a value in the Cubic Foot box to see it in US gallons, or type in the US Gallon box to convert the other way.
- Press ⇄ to swap the two units, or Load example for a typical value.
- Check the charts below for common values; for other units, open the Volume converter.
Formula
US gal = ft³ × 1728 ÷ 231 (≈ 7.48052)
Cubic Foot (ft³) = US Gallon (gal) × 0.133680555556
Both factors come from exact definitions: 1 us gallon = 0.133680555556 cubic feet and 1 cubic foot = 7.48051948052 US gallons (shown to 12 significant digits).
Example
Two conversions worked with the same factors the converter uses:
100 ft³ × 7.48051948052 ≈ 748.052 gal
500 gal × 0.133680555556 ≈ 66.8403 ft³
Cubic Foot to US Gallon chart
Common values from cubic feet to US gallons, rounded to four decimal places.
| Cubic Foot (ft³) | US Gallon (gal) | UK gallons |
|---|---|---|
| 0.5 | 3.7403 | 3.1144 |
| 1 | 7.4805 | 6.2288 |
| 2 | 14.961 | 12.4577 |
| 3 | 22.4416 | 18.6865 |
| 4 | 29.9221 | 24.9153 |
| 5 | 37.4026 | 31.1442 |
| 7.5 | 56.1039 | 46.7163 |
| 10 | 74.8052 | 62.2884 |
| 13.4 | 100.239 | 83.4664 |
| 20 | 149.6104 | 124.5767 |
| 25 | 187.013 | 155.7209 |
| 27 | 201.974 | 168.1786 |
| 50 | 374.026 | 311.4418 |
| 75 | 561.039 | 467.1627 |
| 100 | 748.0519 | 622.8835 |
| 150 | 1,122.08 | 934.3253 |
| 200 | 1,496.1 | 1,245.77 |
| 250 | 1,870.13 | 1,557.21 |
| 500 | 3,740.26 | 3,114.42 |
| 750 | 5,610.39 | 4,671.63 |
| 1,000 | 7,480.52 | 6,228.84 |
| 2,000 | 14,961.04 | 12,457.67 |
| 5,000 | 37,402.6 | 31,144.18 |
US Gallon to Cubic Foot chart
The reverse direction for values people often look up.
| US Gallon (gal) | Cubic Foot (ft³) |
|---|---|
| 1 | 0.1337 |
| 5 | 0.6684 |
| 10 | 1.3368 |
| 20 | 2.6736 |
| 40 | 5.3472 |
| 55 | 7.3524 |
| 75 | 10.026 |
| 100 | 13.3681 |
| 300 | 40.1042 |
| 500 | 66.8403 |
| 748 | 99.9931 |
| 1,000 | 133.6806 |
| 10,000 | 1,336.81 |
| 20,000 | 2,673.61 |
Water and soil volumes measured in cubic feet
| Item | Cubic Foot (ft³) | US Gallon (gal) |
|---|---|---|
| Bag of potting mix, common 2 cu ft size | 2 | 14.961 |
| Aquarium with outer size 48 × 13 × 21 in | 7.5833 | 56.7273 |
| CCF on a US water bill | 100 | 748.0519 |
| Hot tub 7 × 7 ft, 3 ft water depth | 147 | 1,099.64 |
| Pool 16 × 32 ft, 4.5 ft average depth | 2,304 | 17,235.12 |
| Pool 20 × 40 ft, 5 ft average depth | 4,000 | 29,922.08 |
Quick mental estimate
Multiply by 7.5: 40 ft³ → 300 gal. The exact answer is 299.2 gal, so the shortcut runs about 0.3% high.
Use the converter or the charts when the exact figure matters.
The two units
Cubic Foot (ft³): A cubic foot is a cube 1 foot on each side, equal to 1,728 cubic inches or exactly 28.316846592 liters. It is used in the US for room and appliance capacity and gas volumes.
US Gallon (gal): The US liquid gallon is defined as exactly 231 cubic inches, which is 3.785411784 liters. It is the gallon used for gasoline, milk and water in the United States.
Frequently asked questions
How many gallons does my pool hold?
Multiply length × width × average depth in feet, then multiply by 7.48. A 16 × 32 ft pool averaging 4.5 ft deep holds 2,304 ft³, about 17,235 gallons. The swimming pool volume calculator also handles round and oval pools.
What is a CCF on my water bill in gallons?
CCF means 100 cubic feet, which is about 748 US gallons. If a bill shows 8 CCF for a month, the household used roughly 5,984 gallons. The CCF to gallons converter does this for any reading.
Why does a "55-gallon" aquarium measure more than 55 gallons?
Tank names use the outside dimensions and round to a familiar size. A tank 48 × 13 × 21 in on the outside works out to about 7.58 ft³, roughly 56.7 gallons, but glass thickness and the gap below the rim leave less water than that.
How precise is the result?
The converter uses the exact definitions above with browser floating-point arithmetic and shows up to 12 significant digits. The charts round to four decimal places for reading.
Sources
Last updated:
Page address with these inputs: https://kakao.mobile/tools/cubic-foot-to-us-gallon-converter/
Cite or embed this tool
kakaoCalc. (2026, November 8). Cubic Feet to US Gallons Converter (ft³ to gal). https://kakao.mobile/tools/cubic-foot-to-us-gallon-converter/
“Cubic Feet to US Gallons Converter (ft³ to gal).” kakaoCalc, 8 Nov. 2026, kakao.mobile/tools/cubic-foot-to-us-gallon-converter/.
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