Square Inches to Chō (area) (in² to chō)

1 square inch equals 6.505363333×10⁻⁸ chō (area) (rounded).

1 square inch = 6.505363333×10⁻⁸ chō (area)

How to convert square inches to chō (area)

To convert square inches to chō (area), multiply the number of square inches by 6.505363333×10⁻⁸. The factor is rounded to 10 significant digits. To go the other way, multiply chō (area) by 15,371,931.57 (rounded).

chō (area) = square inches × 6.505363333×10⁻⁸

Example: 10 square inches = 6.505363333×10⁻⁷ chō (area).

About these units

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

Chō (area) (chō)

JapaneseTraditional unit (still used in some regions)

3,000 tsubo, about 9,917 m² (roughly one hectare; 2.45 acres). Used for farmland in Japan.

Almost exactly a hectare, the cho is the largest of the everyday Japanese land units. It is 3,000 tsubo, or 1,200,000/121 square metres, about 9,917, which is 0.9917 hectare or roughly 2.45 acres. It is also 100 se or 10 tan, and when no fractional part follows it is often written cho-bu.

Because it is so near a hectare, it is a convenient mental bridge for anyone moving between traditional and metric figures. In Japan it has been used for farmland, and it sits at the top of the tsubo, se and tan ladder.

The name is shared with a unit of length, so the area sense needs to be stated. The area figure used here follows from the 10/33 metre shaku fixed by the 1891 Meiji law, and the 1951 Measurements Law took the traditional units out of official use from 1959.

1 chō (area) = 9,917.355372 square meters (approximately).

Sources: Wikipedia: Japanese units of measurement; Wikipedia: Shaku (unit); Wikipedia: Tsubo

Related conversions

See all area units.