Convert cubic feet to other major volume units.

Convert between feet per second and other major units of velocity.

A measure of length in the English-speaking world. Since the 12th century, the foot has been legally defined as one-third of a yard. Since 1959, one foot = 0.3048 meter exactly; see yard and below.

The foot is only roughly the size of a human foot. The median foot of American males (as many smaller as bigger) is 10.4 inches long, and the female median is an inch smaller. Even 17-year old U.S. Army trainees have a median foot length of only 10.6″, and 95% of them have feet smaller than 11.2″.

The most recent change in the length of the foot was the result of an agreement among the English-speaking countries to eliminate discrepancies between their customary measures. The United States implemented the agreement by an announcement in the Federal Register on July 1, 1959 (“Refinement of Values for the Yard and the Pound”), and since then in the United States the foot has been the international foot = 0.3048 meter exactly. Since the United States is now almost the only country still using the foot, the name has become something of a joke.

U.S. Survey foot

The United States uses a different foot for one activity. When the United States adopted the international yard in 1959, the U.S. Coast and Geodetic Survey, mappers of the nation, objected that converting all their geodetic data to international feet would be a horrendous undertaking. They were authorized to continue to use the previous definition of the foot, that of the Mendenhall order (U.S. Coast and Geodetic Survey Bulletin 26, April 5, 1893), one foot = ¹²⁰⁰⁄₃₉₃₇ meter.

This foot is now known as the U.S. Survey foot, = 1.000 002 international feet, and is used only for land measurements.


In Great Britain, ? – 19th century, a measure of work done by bricklayers, equal to 5 courses of bricks in the height of a wall.

Frederick Danvers Power.
A Pocket-book for Miners and Metallurgists...
London: Crosby Lockwood and Son, 1892.
Page 42.


In Great Britain, ? – 19th century, a sizing system for grindstones. The sum of diameter of the stone and its thickness, both in inches, divided by 8, was the stone's size in "foots".

Simmonds, 1892.


They [grindstones] are classed in eight different sizes, called foots, according to their dimensions, as in the following Table:—

Denomination Diameter.
No. in a
1 foot 10 2 36
2 foots 14 27
3 foots 20 4 18
4 foots 28 4 9
5 foots 35 5 5
6 foots 42 6 3
7 foots 50 6
8 foots 56 8 1

A grindstone foot is 8 inches: the size is found by adding the diameter and thickness together. Thus, a stone 56 inches diameter by 8 thick, making together 64 inches, is an 8-foot stone, of 8 Inches each foot.

Besides the above sizes, grindstones are made, when ordered, of any intermediate dimensions: many are made much larger than any of the above sizes; some as large as 76 inches diameter, and 14 or 15 inches thick, which are a great weigbt, a cubic foot weighing 1 cwt. 1 qr. 14 1bs.-(Rees's Cyclopedia; Bailey's Survey of Durham, p. 43.)

J. R. McCulloch. (Henry Vethake, editor).
A Dictionary, Practical, Theoretical, and Historical, of Commerce and Commercial Navigation. Vol. 1.
Philadelphia: Thomas Wardle, 1843.
Page 719.


In Cornwall, ? – 19th century, a unit used for measuring tin ore, washed and ready for smelting, originally two gallons, later = 60 pounds, and finally nominal.



FOOT. An ancient measure for black Tin; two gallons; now a nominal measure, but in weight 60 lbs.

William Pryce.
Mineralogia Cornubiensis. A Treatise on Minerals, Mines, and Mining: Containing the Theory and Natural History...etc.
London: Printed and sold for the author by James Phillips, 1778.
“Black tin” is tin ore, not to be confused with “block tin”.


They measure their blacke Tynne, by the Gill, the Topliffe, the Dish and the Foote, which containeth: a pint, a pottel, a gallon, and towards two gallons.

Richard Carew.
A Survey of Cornwall...A New Edition.
London: Printed for B. Law, 1769.


In the past, “foot” was also used as a term for a cubic foot (foot as in sense 1, above), just as today a yard of concrete is a cubic yard. A specific example is provided below.


They shall be equipped with a ⅝-ft. burner, a 6-in. concave mirror and a clear, plain front glass.

Burners.—A ⅝-ft. burner is one that consumes ⅝ cu. ft. of gas per hour at normal gas pressure.

Motor-Vehicle Acetylene Head-lamps.
S.A.E. Handbook, 1928 edition.
New York: Society of Automotive Engineers, 1928.
Page 83.

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