Cubic Feet to Gallons Converter
A US liquid gallon is exactly 231 cubic inches and a cubic foot is exactly 1,728 of them, so cubic feet to gallons is one multiplication: gallons = cubic feet × 1728/231, a fraction that reduces to 576/77 and runs 7.48051948051948 and repeating in decimal. Nothing in that is measured, so the ratio is exact by definition: the international foot is defined as exactly 0.3048 metres and the US liquid gallon as exactly 3.785411784 litres, which is those 231 cubic inches. Only the decimal gets rounded, to twelve significant digits here, so 1 ft³ reads 7.48051948052 gal, 10 ft³ reads 74.8051948052 gal and 100 ft³, the CCF a water utility bills in, reads 748.051948052 gal. The UK imperial gallon is a different and larger unit, exactly 4.54609 litres, so the same cubic foot is 6.22883545904 imperial gallons instead. This page opens the converter on the Volume category with cubic feet in the From box and US gallons in the To box, whatever pair you converted last, and under the answer it lists the same volume in millilitres, litres, cubic metres, teaspoons, tablespoons, US fluid ounces, cups, pints and quarts, with the imperial units and cubic inches behind the uncommon units switch.
1 ft³ in every volume unit
Common questions
- How many gallons are in a cubic foot?
- 7.48051948052 US gallons, which is 1,728 cubic inches divided by 231, or the fraction 576/77. Multiply straight through for any size: 2 ft³ is 14.961038961 gal, 5 ft³ is 37.4025974026 gal and 10 ft³ is 74.8051948052 gal. Rounding the factor to 7.48 is off by about 0.007%, which is nothing on one cubic foot and 0.052 gallons on a hundred, where 7.48 × 100 gives 748 and the converter prints 748.051948052. Copy result copies the headline exactly as printed, without the thousands separators.
- What is 100 cubic feet in gallons, the CCF on a water bill?
- 748.051948052 US gallons, which utilities round to 748. CCF and HCF both mean one hundred cubic feet, so a bill for 6 CCF is 600 ft³: type 600 and the answer is 4,488.31168831 gallons. The same 600 ft³ appears as 16,990.1079552 litres in the list under the answer, without changing the units yourself.
- How do I convert gallons back to cubic feet?
- Divide by 7.48051948052, or multiply by 231/1728, which is exactly 0.133680555556 cubic feet per US gallon. So 50 gallons is 6.68402777778 ft³ and 100 gallons is 13.3680555556 ft³. The Swap units button between the two boxes turns this page into a gallons to cubic feet converter without a reload, and the number you typed stays where it is while the pair reverses.
- Is this a US gallon or an imperial gallon?
- The To box here is the US liquid gallon, exactly 3.785411784 litres. The imperial gallon still used in the UK is exactly 4.54609 litres, about 20% larger, so one cubic foot is 6.22883545904 imperial gallons against 7.48051948052 US gallons. To see it, tick the uncommon units switch in the readout, which adds the imperial fluid ounce, imperial pint, imperial gallon and cubic inch to the list, or choose Gallon (imperial) in the To box, which lists every volume unit whether the switch is on or not.
- Does it matter whether the cubic feet hold water, fuel or air?
- No. This is a volume to volume conversion, so it is geometry and nothing else: a cubic foot of water and a cubic foot of air are both 7.48051948052 gallons of space. Weight is what changes with the contents, and that needs a density this converter does not carry, so its Mass category converts pounds, kilograms and ounces against each other rather than turning a volume into a weight.
- How do I work out the cubic feet in the first place?
- Multiply length by width by height with every measurement in feet. A tank 4 ft long, 2 ft wide and 2 ft deep is 16 ft³, and this page converts that to 119.688311688 gallons. If you measured in inches, divide the cubic inches by 1,728 first, since a foot is 12 inches and 12 × 12 × 12 = 1,728. For a cylinder, a cone or a pool with a sloping floor, the volume calculator linked below does the shape and prints US gallons next to the cubic feet.
- Why does the page open on cubic feet and gallons?
- Because a page that names a pair should arrive on that pair. The preset sets the Volume category, cubic feet in From and US gallons in To, ahead of whatever the converter remembered from your last visit. Your own saved pair survives it: go back to the main unit converter and it is still on the units you left it on. The value you last typed does come with you, since that is usually the number you are still working with.
Conversion factors are the exact legal definitions where one exists. An inch is exactly 2.54 cm and a pound exactly 0.45359237 kg, so those conversions are exact rather than approximate. Temperature uses offsets rather than factors, and that is shown in the working.