cubic foot
Unit systemImperial and US Customary
Unit ofVolume
Symbolft3, cu ft
1 ft3 in ...... is equal to ...
   US Customary   1728 in3
127 yd3
   SI units   0.02831685 m3

The cubic foot (symbol ft3 or cu ft)[1] is an imperial and US customary (non-metric) unit of volume, used in the United States and the United Kingdom. It is defined as the volume of a cube with sides of one foot (0.3048 m) in length. Its volume is 28.3168 L (about 135 of a cubic metre).


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1 cubic foot  = 1728 cubic inches
= 127 of a cubic yard
0.037037 yd3
= 0.028316846592 m3
= 28.316846592 L
= 57677 US fluid gallons
7.4805 US fl gal
= 7372877 US fluid ounces
957.5065 US fl oz
≈ 6.2288 imperial gallons
≈ 996.61 imperial fluid ounces
≈ 0.80356 US bushels
≈ 0.17811 oil barrel

Symbols and abbreviations

The IEEE symbol for the cubic foot is ft3.[1] The following abbreviations are used: cubic feet, cubic foot, cubic ft, cu feet, cu foot, cu ft, cu.ft, cuft, cb ft, cb.ft, cbft, cbf, feet3, foot3, ft3, feet/-3, foot/-3, ft/-3.[citation needed]

Larger multiples are in common usage in commerce and industry in the United States:

Cubic foot per second and related flow rates

The IEEE symbol for the cubic foot per second is ft3/s.[1] The following other abbreviations are also sometimes used:

The flow or discharge of rivers, i.e., the volume of water passing a location per unit of time, is commonly expressed in units of cubic feet per second or cubic metres per second.

Cusec is a unit of flow rate,[2] used mostly in the United States in the context of water flow, particularly of rivers and canals.

Conversions: 1 ft3s−1 = 0.0283168 m3/s = 28.3168 L/s = 1.699011 m3/min = 1,699.011 L/min

Cubic foot per minute

The IEEE symbol for the cubic foot per minute is ft3/min.[1] The following abbreviations are used:

Cubic feet per minute is used to measure the amount of air that is being delivered, and is a common metric used for carburettors,[3] pneumatic tools, and air-compressor systems.[4]

Standard cubic foot

Main article: Standard cubic foot

See also: Standard cubic foot per minute

A standard cubic foot (abbreviated scf) is a measure of quantity of gas, sometimes[clarification needed] defined in terms of standard temperature and pressure as a cubic foot of volume at 60 degrees Fahrenheit (15.56 °C; 288.71 K) and 14.7 pounds per square inch (PSI) (1.01 bar; 101.35 kPa) of pressure.[citation needed]

See also


  1. ^ a b c d IEEE Standard Letter Symbols for Units of Measurement (SI Customary Inch-Pound Units, and Certain Other Units). 2004-09-24. pp. 1–30. doi:10.1109/IEEESTD.2004.94618. ISBN 978-1-5044-0928-5. STD95220 STDPD95220 STDPL95220. Archived from the original (PDF or hardcopy) on 2018-06-12. Retrieved 22 December 2019. ((cite book)): |website= ignored (help) [1], ISBN 978-0-7381-3997-5, ISBN 978-0-7381-3998-2.
  2. ^ Rowlett, Russ. "Units: C". How Many? A Dictionary of Units of Measurement. University of North Carolina at Chapel Hill. Archived from the original on January 9, 2018. Retrieved August 2, 2020.
  3. ^ "Carburetor CFM Racing". Summit Racing. Retrieved February 7, 2019.
  4. ^ "Easy Guide to Rotary Screw Air Compressors for Vehicles". October 16, 2018. Retrieved October 30, 2018.