Chains to Meters (ch to m)

1 chain equals 20.1168 meters exactly.

1 chain = 20.1168 meters

How to convert chains to meters

To convert chains to meters, multiply the number of chains by 20.1168. This factor is exact. To go the other way, multiply meters by 0.04970969538 (rounded).

meters = chains × 20.1168

Example: 10 chains = 201.168 meters.

About these units

Chain (ch)

US & ImperialTraditional unit (still used in some regions)

22 yards or 66 feet (20.1168 m), also called Gunter's chain. A surveying unit; a cricket pitch is one chain long.

Edmund Gunter, an English mathematician, devised a surveying method in 1620 around a measuring chain of 100 links. Its length of 66 feet was chosen because ten square chains make exactly one acre, so land area could be worked out with simple decimal arithmetic. Surveyors' chains had appeared in Dutch and English sources a few years earlier, but his version gave the chain its standard length and its name. John Ogilby's road atlas Britannia, published in 1675, shows it was widely accepted by then.

The chain equals 22 yards, four rods or exactly 20.1168 m, and 80 chains make a mile. Earlier Scots and Irish chains were longer, at about 74 and 84 feet. American public land surveys from the 1785 Land Ordinance relied on it, and sections are 80 chains on a side. The chain also outlived the surveyor's tool itself: a cricket pitch is one chain between the wickets, British railways still give locations in miles and chains, and fire agencies measure spread in chains per hour.

1 chain = 20.1168 meters (exactly).

Sources: Wikipedia: Chain (unit); NIST SP 811, Appendix B.8 (length conversion factors)

Meter (m)

Metric (SI)Current unit

The SI base unit of length. Since 1983 it is defined as the distance light travels in a vacuum in 1/299,792,458 of a second.

Meter comes from the Greek metron, a measure. In 1791 the French National Assembly defined it as one ten-millionth of the distance from the equator to the North Pole along a great circle through Paris, after rejecting the length of a seconds pendulum because that length changes with local gravity. The surveyors Delambre and Méchain measured the meridian arc, and in 1799 a platinum bar known as the Mètre des Archives became the physical standard. NIST notes that this Earth-based meter turned out to be about 0.2 mm shorter than the true pole-to-equator fraction it was meant to represent.

The 1875 Treaty of the Meter created the CGPM and the BIPM to look after common standards, and in 1889 a platinum-iridium prototype bar took over; the original is still kept at the BIPM. In 1960 the meter was tied to 1,650,763.73 wavelengths of an orange-red krypton-86 line, and in 1983 to the speed of light, which made length a quantity derived from the time standard. The 2018 revision reworded that definition without changing the meter's size. NIST offers a handy yardstick for scale: a pace, meaning two steps, is roughly a meter or a yard.

The meter is the reference unit for length on this site.

Sources: BIPM: history of the metre; NIST: the meter and the SI redefinition; Wikipedia: Metre

Related conversions

See all length units.