Square Inches to Hectares (in² to ha)

1 square inch equals 6.4516×10⁻⁸ hectares exactly.

1 square inch = 6.4516×10⁻⁸ hectares

How to convert square inches to hectares

To convert square inches to hectares, multiply the number of square inches by 6.4516×10⁻⁸. This factor is exact. To go the other way, multiply hectares by 15,500,031 (rounded).

hectares = square inches × 6.4516×10⁻⁸

Example: 10 square inches = 6.4516×10⁻⁷ hectares.

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

Hectare (ha)

Metric (SI)Current unit

10,000 square meters (2.471 acres). The standard unit for land and agricultural areas outside the US.

Hecto plus are: the name was coined in French, and are itself comes from the Latin area, meaning an open space. The French law of 18 Germinal, Year III (7 April 1795) defined the are as 100 square meters, and the hectare followed as 100 ares, or 10,000 square meters. The unit is therefore a product of the original French metric reforms rather than of later SI work, which is one reason its official status has always been slightly awkward.

When the SI was set up in 1960 the are was not recognized, and the hectare was classed as a non-SI unit accepted for use with it. In practice it is the standard unit for land ownership, planning and agriculture in the European Union, the United Kingdom, Canada, Australia, New Zealand and South Africa, while the United States and Myanmar stay with the acre. A hectare is a square 100 meters on each side, about the size of Trafalgar Square, and equals roughly 2.47 acres. One hundred of them make a square kilometer.

1 hectare = 10,000 square meters (exactly).

Sources: Wikipedia: Hectare; Wikipedia: Are (unit); NIST Guide to the SI, Appendix B.8: conversion factors

Related conversions

See all area units.