Cubic Feet to Gallons Calculator
Convert cubic feet to US and imperial gallons — and back. Exact NIST and UK statutory factors, with litres, cubic inches, and cubic metres in the mix.
1 Cubic feet (ft³) =
7.48
- In US gallons (liquid)
- 7.48
- In imperial gallons (UK)
- 6.23
- In litres
- 28.32
Converted via the litre pivot — 28.316846592 L per cu_ft, 3.785411784 L per us_gal to reach US gallons (liquid). 1 ft³ = 28.316 846 592 L exact (foot = 0.3048 m, NIST); US gal = 231 in³ = 3.785 411 784 L exact; imperial gal = 4.546 09 L exact (UK W&M Act 1985).
How to use this calculator
Enter a value, choose the unit you have in "From", and the unit you want in "To". The result updates instantly, and the breakdown always shows US gallons, imperial gallons, and litres. Swapping the From and To selects flips the direction — gallons back to cubic feet.
How the calculation works
Every unit converts through an intermediate value in litres, using exact factors. A cubic foot is 0.3048³ = 0.028 316 846 592 m³ = 28.316 846 592 litres, because the international foot is exactly 0.3048 m (NIST). A US liquid gallon is defined as 231 cubic inches, which is 3.785 411 784 litres. An imperial (UK) gallon is 4.546 09 litres exactly (Weights and Measures Act 1985). So 1 ft³ ÷ 3.785 411 784 = 7.480 52 US gallons, or 1 ft³ ÷ 4.546 09 = 6.228 84 imperial gallons.
Worked example
A fish tank measuring 2 ft × 1 ft × 1 ft holds 2 cubic feet. In US gallons that is 2 × 7.480 52 = 14.96 US gallons; in imperial gallons it is 2 × 6.228 84 = 12.46 imperial gallons; and 2 × 28.3168 = 56.63 litres. Going the other way, a 50 US-gallon drum is 50 × 0.133 681 = 6.68 cubic feet.
Frequently asked questions
How many gallons are in a cubic foot?
One cubic foot holds 7.480 52 US liquid gallons, or 6.228 84 imperial (UK) gallons. The two differ because an imperial gallon (4.546 09 L) is about 20% larger than a US gallon (3.785 41 L), so a cubic foot contains fewer of them.
How do I convert cubic feet to US gallons?
Multiply the number of cubic feet by 7.480 52. For example, 10 ft³ × 7.480 52 = 74.81 US gallons. The exact factor comes from a US gallon being 231 cubic inches and a cubic foot being 1,728 cubic inches: 1,728 ÷ 231 = 7.480 52.
How many cubic feet are in a gallon?
A US gallon is 0.133 681 cubic feet (1 ÷ 7.480 52), and an imperial gallon is 0.160 544 cubic feet. So it takes just under 7½ US gallons, or a little over 6¼ imperial gallons, to fill one cubic foot.
What is the difference between US and imperial gallons here?
The US liquid gallon is 3.785 411 784 litres (231 in³); the imperial gallon is 4.546 09 litres. Because the imperial gallon is bigger, any cubic-feet value converts to a smaller number of imperial gallons than US gallons. Pick the option that matches your country: US gallons in the United States, imperial for older UK figures.
How many litres are in a cubic foot?
Exactly 28.316 846 592 litres, because a cubic foot is 0.028 316 846 592 cubic metres and a litre is one-thousandth of a cubic metre. That is a handy pivot: convert cubic feet to litres first, then divide by 3.785 41 for US gallons or 4.546 09 for imperial gallons.
Does this work for gas volumes like natural gas (CCF)?
It converts the physical volume only. Utility units such as CCF (100 cubic feet) or MCF measure a volume of gas at stated conditions, not liquid gallons, so a direct cubic-feet-to-gallons conversion is not meaningful for billed gas energy. Use this converter for liquids, tanks, and containers.