Cubic foot

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 1⁄35 of a cubic metre).

cubic foot
Gas meter with volume measured in cubic feet
General information
Unit system	Imperial and US Customary
Unit of	Volume
Symbol	ft3, cu ft
Conversions
1 ft3 in ...	... is equal to ...
US Customary	1728 in3 1⁄27 yd3
SI units	0.02831685 m3

Conversions

1 cubic foot	= 1728 cubic inches
	= 1⁄27 of a cubic yard
		≈ 0.037037 yd3
	= 0.028316846592 m3
		= 28.316846592 L
	= 576⁄77 US fluid gallons
		≈ 7.4805 US fl gal
	= 73728⁄77 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:

• CCF or HCF: Centum (Latin hundred) cubic feet; i.e., 100 ft³
  • Used in the billing of natural gas and water delivered to households.
• MCF: Mille (Latin thousand) cubic feet; i.e., 1000 ft³
• MMCF: Mille mille cubic feet; i.e., 1000000 ft³
• MMCFD: MMCF per day; i.e., 1000000 ft³/d
  • Used in the oil and gas industry.
• BCF or TMC: Billion or thousand million cubic feet; i.e., 1000000000 ft³
  • TMC is usually used for referring to storage capacity and actual storage volume of storage dams.
• TCF: Trillion cubic feet; i.e., 1000000000000 ft³
  • Used in the oil and gas industry.

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:

• ft³/sec
• cu ft/s
• cfs or CFS
• cusec
• second-feet

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:

• cu ft/min
• cufm
• cfm or CFM
• cfpm or CFPM

Cubic feet per minute is used to measure the amount of air that is being delivered, and is a common metric used for carburetors,^[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 °F (16 °C; 289 K) and 14.7 pounds per square inch (1.01 bar; 101 kPa) of pressure.^{[citation needed]}

See also

• Board foot
• Conversion of units
• Cord (unit)
• Cube (arithmetic), cube root
• Cubic inch
• Cubic yard
• Orders of magnitude (volume) for a comparison with other volumes
  • Orders of magnitude (one cubic millimetre to one cubic metre)
• Square foot
• Therm, a unit of natural gas approximately equal to 100 cubic feet
• Cubic metre per second

References

1. IEEE Standard Letter Symbols for Units of Measurement (SI Units, Customary Inch-Pound Units, and Certain Other Units) (Revision of IEEE Std 260.1-1993). IEEE Std 260.1-2004 (2004 ed.). Piscataway, N.J.: IEEE. 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. , 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. Archived from the original on April 27, 2021. Retrieved February 7, 2019.
4. "Easy Guide to Rotary Screw Air Compressors for Vehicles". VMACAir.com. October 16, 2018. Retrieved October 30, 2018.