Linear Measure: Units of Length
12 inches = 1 foot; 3 feet = 1 yard; 5½ yards = 1 rod; 40 rods = 1 furlong; 8 furlongs = 1 mile (5,280 feet). Since 1959 the inch is exactly 2.54 cm.
Length converter
Source: NIST Handbook 44, Appendix C (Units of length) · All sources
The table of linear measure as it appears in NIST Handbook 44, plus the older and specialist units you still meet in deeds, horse racing, sailing and old books.
Table of linear measure
12 inches = 1 foot · 3 feet = 1 yard · 5½ yards = 1 rod · 40 rods = 1 furlong · 8 furlongs = 1 mile 1 mile = 1,760 yards = 5,280 feet = 63,360 inches · 3 miles = 1 league| Unit | Inches | Feet | Meters |
|---|---|---|---|
| 1 line | 0.0833 in | 0.0069 ft | 0.002117 m |
| 1 inch | 1 in | 0.0833 ft | 0.0254 m |
| 1 hand | 4 in | 0.3333 ft | 0.1016 m |
| 1 link (Gunter's) | 7.92 in | 0.66 ft | 0.201168 m |
| 1 span | 9 in | 0.75 ft | 0.2286 m |
| 1 foot | 12 in | 1 ft | 0.3048 m |
| 1 cubit | 18 in | 1.5 ft | 0.4572 m |
| 1 yard | 36 in | 3 ft | 0.9144 m |
| 1 fathom | 72 in | 6 ft | 1.8288 m |
| 1 rod (pole, perch) | 198 in | 16.5 ft | 5.0292 m |
| 1 chain (Gunter's) | 792 in | 66 ft | 20.1168 m |
| 1 furlong | 7,920 in | 660 ft | 201.168 m |
| 1 mile (statute) | 63,360 in | 5,280 ft | 1,609.344 m |
| 1 league | 190,080 in | 15,840 ft | 4,828.032 m |
| 1 nautical mile | 72,913.3858 in | 6,076.1155 ft | 1,852 m |
Surveyors' (Gunter's) chain measure
7.92 inches = 1 link · 100 links = 1 chain = 4 rods = 66 feet · 10 chains = 1 furlong · 80 chains = 1 mileEdmund Gunter introduced the 66-foot chain in 1620. It fitted the existing English units neatly: an acre is 1 chain by 1 furlong (43,560 square feet). US public land surveys used it for centuries, so chains and links still appear in old property deeds.
Nautical and body measures
- Fathom: 6 feet, used for water depth. Originally the span of a sailor's outstretched arms.
- Nautical mile: exactly 1,852 m (about 6,076 feet), close to one minute of latitude. One knot is one nautical mile per hour.
- Hand: 4 inches, still used for the height of horses (a 15.2 hand horse is 15 hands 2 inches, or 62 inches).
- Span (9 inches) and cubit (18 inches): old body-based measures found in historical and biblical texts. Their real length varied by place and period.
How the inch became metric
Since July 1, 1959, the US and the Commonwealth countries have defined the yard as exactly 0.9144 meter, which makes the inch exactly 2.54 centimeters. Before that, the US inch was very slightly longer than the British one. Every value in the table above uses the 1959 definitions and is exact, except the line, which repeats (1/12 inch = 2.1166… mm).
Frequently asked questions
How many feet are in a rod?
16.5 feet (5½ yards, 5.0292 m). The rod is also called a pole or perch.
How long is a furlong?
660 feet, which is 220 yards, 40 rods or 10 chains (201.168 m). There are 8 furlongs in a mile.
How long is a league?
In English-speaking use, a league is 3 statute miles (about 4.83 km). Older and foreign leagues varied, so a league in a historical text may not be exactly 3 miles.
What is a line as a unit of length?
A line is 1/12 of an inch (about 2.12 mm), used historically for small measurements. Button makers use a different 'ligne' of 1/40 inch, so a 40-line button is 1 inch across.
What is a chain in surveying?
Gunter's chain is 66 feet long, made of 100 links of 7.92 inches. 10 square chains make an acre, and 80 chains make a mile, which made it easy to survey land in English units.
Is the US survey foot still used?
No. NIST retired the US survey foot (1200/3937 m) at the end of 2022. All US measurements now use the international foot of exactly 0.3048 m; the difference is about 2 parts per million.
Sources
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- November 5, 2026
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