Links to Millimeters (li to mm)

1 link equals 201.168 millimeters exactly.

1 link = 201.168 millimeters

How to convert links to millimeters

To convert links to millimeters, multiply the number of links by 201.168. This factor is exact. To go the other way, multiply millimeters by 0.004970969538 (rounded).

millimeters = links × 201.168

Example: 10 links = 2,011.68 millimeters.

About these units

Link (li)

US & ImperialTraditional unit (still used in some regions)

One hundredth of a chain, 7.92 inches (0.201168 m). A surveying unit, one link of Gunter's chain.

Each link is the small piece that makes up a surveyor's chain, and the chain's hundred links gave decimal fractions to a system built on feet and yards. A single link measures 7.92 inches, or exactly 0.201168 m, because it is one hundredth of a 66-foot chain. Because of that, distances could be recorded in whole chains and links without fractions.

Edmund Gunter introduced the 100-link chain in England in 1620, and the link spread across the English-speaking world with it. Twenty-five links make a rod, 1,000 make a furlong and 8,000 make a mile. The exact size depends on which foot is used: the pre-1959 imperial foot gives about 201.1677 mm, the US survey foot about 201.1684 mm, and the international foot exactly 201.168 mm. Since the US survey foot was retired after 2022, the international value applies there too. Metric and electronic surveying replaced links in the twentieth century, though old deeds still use them.

1 link = 0.201168 meters (exactly).

Sources: Wikipedia: Link (unit); Wikipedia: Chain (unit)

Millimeter (mm)

Metric (SI)Current unit

One thousandth of a meter. Used in engineering, manufacturing and rainfall measurement.

Carl Friedrich Gauss put the millimeter at the base of his 1832 proposal for absolute units, pairing it with the milligram and the second, although the centimeter-based CGS system later won out among scientists. The name combines the metric prefix milli-, from the Latin for one thousand, with the meter. Since 1983 a millimeter has been tied to the speed of light: it is the distance light covers in 1/299,792,458,000 of a second.

Millimeters are the language of fine mechanical work. Standard rulers are divided into them, digital calipers commonly read to 0.01 mm, and mechanical pencil leads come in 0.5 and 0.7 mm. Copy paper is about 0.1 mm thick, and a thin hair, at 0.02 to 0.04 mm across, is close to the smallest thing the naked eye can see. A wave with a frequency of 300 GHz has a wavelength of 1 mm. An inch is exactly 25.4 mm. One trap for readers in the United States is that mil there traditionally means a thousandth of an inch, not a millimeter.

1 millimeter = 0.001 meters (exactly).

Sources: Wikipedia: Millimetre; Wikipedia: Centimetre-gram-second system of units; NIST Guide to the SI, Appendix B.8: conversion factors

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