Skip to content
UnitCalculators.com

Cubic feet to US gallons

Multiply cubic feet by 7.4805 to get US gallons.

1 ft³ = 7.4805 galNIST HB 44
ft³
74.8052gal

10 ft³ = 74.8052 gal

How to convert cubic feet to US gallons

The US gallon is the US liquid gallon, exactly 231 cubic inches (3.785411784 litres). The cubic foot is a cube one foot on each side — exactly 28.316846592 litres (0.3048³ m³), about 7.48 US gallons.

Worked example — 10 ft³: 10 × 7.4805 = 74.8052 gal.

Cubic feet to US gallons table

Common conversions.
Cubic feetUS gallons
0.5 ft³3.7403 gal
1 ft³7.4805 gal
2 ft³14.961 gal
5 ft³37.4026 gal
10 ft³74.8052 gal
20 ft³149.6104 gal
50 ft³374.026 gal
100 ft³748.0519 gal
500 ft³3,740.2597 gal

Reverse and related

About cubic feet and US gallons

Cubic foot (ft³)

1 ft³ = 7.4805 gal

Definition. A cube one foot on each side — exactly 28.316846592 litres (0.3048³ m³), about 7.48 US gallons

History and origin

The cubic foot is the volume of a cube one foot on each side, built from the international foot. It equals about 28.32 litres, or roughly 7.48 US gallons.

Current use

Cubic feet measure the capacity of refrigerators and freezers, natural-gas supply and shipping volume in the United States.

Source: NIST Handbook 44, Appendix C §2 (U.S. Customary Units) and §5 (Tables of Equivalents)

US gallon (gal)

1 gal = 0.133681 ft³

Definition. The US liquid gallon, exactly 231 cubic inches (3.785411784 litres)

History and origin

The US gallon derives from the old English wine gallon of 231 cubic inches, a value the United States kept when Britain moved to a larger imperial gallon in 1824. It equals exactly 3.785411784 litres.

Current use

The gallon is the everyday US unit for fuel, milk and paint; the imperial gallon used in the UK and Canada is about 20 percent larger.

Source: NIST Handbook 44, Appendix C §2 (U.S. Customary Units) and §5 (Tables of Equivalents)

Where people use this

Cubic feet: appliance capacity, natural gas, shipping. US gallons: fuel in the US, large containers, paint. 1 cubic foot is about 7.48 US gallons.

How we know this is right
The factor is fixed by the standards that define the units, not chosen — so it is exact, not a measurement:
1 gal = 0.1336805556 ft³, so 1 ft³ = 1 ÷ 0.1336805556 = 7.4805 gal.

Every value is carried to full double precision; the display is rounded.

Both units are defined in NIST Handbook 44, Appendix C §2 (U.S. Customary Units) and §5 (Tables of Equivalents).

Questions people ask

How many gallons in a cubic foot?

One cubic foot is about 7.48 US gallons.

How many gallons is 10 cubic feet?

10 cubic feet is about 74.8 gallons.

How many cubic feet is 100 gallons?

100 US gallons is about 13.4 cubic feet.