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U.S. Survey Foot: Revised Unit Conversion Factors

Approximate decimal SI equivalents for measures commonly given in U.S. survey feet and exact equivalents for the foot that will be adopted after December 31, 2022 and published in NIST SP 811, The NIST Guide for the use of the International System of Units.

Unit of measure based on feet

Type of quantity

U.S. survey foot
(approximate)

foot
(exact)

foot (ft)

length

0.304 800 6 m

0.304 8 m

mile (mi)

length

1609.347 m

1609.344 m

chain (ch)

length

20.116 84 m

20.116 8 m

link (li)

length

0.201 168 4 m

0.201 168 m

rod (rd), pole, perch

length

5.029 21 m

5.029 2 m

furlong (fur)

length

201.168 4 m

201.168 m

fathom

length

1.828 804 m

1.828 8 m

acre (ac)

area

4046.872 609 9 m2

4046.856 422 4 m2

Created September 23, 2019, Updated October 16, 2019