Feet to US Survey Feet (ft to ft (US))

1 foot equals 0.999998 US survey feet exactly.

1 foot = 0.999998 US survey feet

How to convert feet to US survey feet

To convert feet to US survey feet, multiply the number of feet by 0.999998. This factor is exact. To go the other way, multiply US survey feet by 1.000002 (rounded).

US survey feet = feet × 0.999998

Example: 10 feet = 9.99998 US survey feet.

About these units

Foot (ft)

US & ImperialCurrent unit

12 inches. Defined as exactly 0.3048 meters. Still the standard unit for height, altitude in aviation and room dimensions in the US and UK.

Human anatomy supplied the idea: an adult foot is roughly 15 percent of body height. Ancient cultures turned that into standards, but not the same one. The Greek pous was about 302 mm, the standard Roman pes about 295.7 mm, and a Harappan foot of about 335 mm has been reported from the Indus Valley. Historically, a foot fell somewhere between about 250 and 335 mm. Charlemagne tried to standardize units around 790 with little lasting success, and in 1593 English law fixed the statute mile at 5,280 feet.

The modern foot dates from the 1959 International Yard and Pound Agreement, which defined the yard as exactly 0.9144 meter and so the foot as exactly 0.3048 meter; the UK adopted it on 1 January 1964. The US survey foot, defined in 1893 as 1200/3937 meter, was deprecated on 31 December 2022. Feet remain in everyday use for height and rooms in the US, and ISO shipping containers are defined in them. Aviation altitudes use them too: flight level 330 means 33,000 feet.

1 foot = 0.3048 meters (exactly).

Sources: Wikipedia: Foot (unit); Wikipedia: Mile; NIST Guide to the SI, Appendix B.8: conversion factors

US Survey Foot (ft (US))

US land surveyHistorical unit (no longer in standard use)

Exactly 1200/3937 meters, about 2 parts per million longer than the international foot. Retired in the US at the end of 2022 but still found in older land records.

Two feet coexisted in the United States for sixty-three years. The Mendenhall Order of 1893 tied American units to the metre at 39.37 inches to the metre, which makes the survey foot exactly 1200/3937 m, about 0.3048006 m. In 1959 the international foot was set at exactly 0.3048 m for industry and trade, but the older foot was kept for geodetic work until control networks could be readjusted. That readjustment was finished in 1986, yet the survey foot stayed in use.

The two differ by about 2 parts per million. That is trivial for a house lot but adds up in the State Plane Coordinate System, where coordinates can lie hundreds of thousands of feet from their origin. NIST and the National Geodetic Survey announced that the survey foot should not be used after December 31, 2022, with the international foot replacing it, leaving it for historic and legacy data. Before that, state laws varied: about 40 of 56 jurisdictions based surveying on the survey foot, six on the international foot, and ten did not specify.

1 US survey foot = 0.3048006096 meters (approximately).

Sources: NIST: U.S. survey foot; Wikipedia: Foot (unit)

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