Inches to Chains (in to ch)

1 inch equals 0.001262626263 chains (rounded).

1 inch = 0.001262626263 chains

How to convert inches to chains

To convert inches to chains, multiply the number of inches by 0.001262626263. The factor is rounded to 10 significant digits. To go the other way, multiply chains by 792.

chains = inches × 0.001262626263

Example: 10 inches = 0.01262626263 chains.

About these units

Inch (in)

US & ImperialCurrent unit

1/12 of a foot. Defined as exactly 25.4 millimeters since 1959, when the US and Commonwealth countries agreed a common international inch.

Latin uncia, meaning one-twelfth, is the root of both inch and ounce, and it passed into Old English as ynce. Roman measurers divided their foot into twelve unciae, and the English inch kept that twelfth. After 1066 an inch was reckoned as three barleycorns, and a 1324 statute attributed to Edward II spelled out the definition as three grains of barley, dry and round, placed end to end lengthwise. For centuries the inch was simply a twelfth of a foot, or a thirty-sixth of a yard, and the US and UK each kept their own copy of the standard yard.

Those copies differed slightly until the 1959 international agreement fixed the yard at exactly 0.9144 meter, which made the inch exactly 25.4 millimeters. The US adopted it in 1959 and the UK ratified it in 1963, effective 1964. Today the inch is still the customary unit in the United States and Canada, and the UK keeps it on road signs. Worldwide it also names display diagonals, wheel rims, tire codes and pipe sizes.

1 inch = 0.0254 meters (exactly).

Sources: Wikipedia: Inch; Wikipedia: Yard; NIST Guide to the SI, Appendix B.8: conversion factors

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)

Related conversions

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