Square Chains to Square Inches (sq ch to in²)

1 square chain equals 627,264 square inches exactly.

1 square chain = 627,264 square inches

How to convert square chains to square inches

To convert square chains to square inches, multiply the number of square chains by 627,264. This factor is exact. To go the other way, multiply square inches by 0.000001594225079 (rounded).

square inches = square chains × 627,264

Example: 10 square chains = 6,272,640 square inches.

About these units

Square Chain (sq ch)

US & ImperialTraditional unit (still used in some regions)

484 square yards (404.69 m²), one tenth of an acre. A surveying unit.

Surveyors rather than farmers gave this unit its shape. In 1620 the English clergyman and mathematician Edmund Gunter devised a measuring chain of 100 links that was 66 feet long, and by 1675 it was in wide use. A square chain, 66 feet by 66 feet, covers 4,356 square feet, or 484 square yards. The convenient result is that ten of them make exactly one acre, so a plot measured in chains could be turned into acres by moving a decimal point.

That arithmetic was the reason the US adopted the chain. A report by Thomas Jefferson in 1784 led to the Land Ordinance of 1785, which required the chain for surveying the public lands, and many American property lines still trace back to chain measurements. In metric terms a square chain is about 404.69 square meters. The linear chain remains in niche use, for example in railway milepost distances in Britain, in wildfire spread rates in the United States, and as the length of a cricket pitch.

1 square chain = 404.6856422 square meters (approximately).

Sources: Wikipedia: Chain (unit); Wikipedia: Acre; Wikipedia: Rod (unit)

Square Inch (in²)

US & ImperialCurrent unit

A square one inch on a side, exactly 6.4516 cm². Used for small parts and for pressure (pounds per square inch).

Latin uncia, one twelfth, gave English the inch, which Old English borrowed as ynce. A statute of Edward II in 1324 defined it as three barleycorns, dry and round, set end to end, and the barleycorn remained the base for centuries after 1066. The modern square inch rests on a 20th-century agreement: the United States adopted a yard of exactly 0.9144 meter on 1 July 1959, the United Kingdom followed effective 1 January 1964, and the inch became exactly 25.4 mm.

Squaring that gives exactly 6.4516 cm² for one square inch, and one square meter is about 1,550 of them. Its best-known descendant is the pound per square inch, psi, the pressure unit still used for American tires and air tanks: atmospheric pressure at sea level is about 14.7 psi, a car tire is typically inflated to around 32 psi above the surrounding air, and one psi is about 6.895 kilopascals. The square inch itself is common in the US and UK for small parts and printed material.

1 square inch = 0.00064516 square meters (exactly).

Sources: Wikipedia: Square inch; Wikipedia: Inch; Wikipedia: Pounds per square inch

Related conversions

See all area units.