Square Inches to Rai (Thai) (in² to rai)

1 square inch equals 4.03225×10⁻⁷ rai (Thai) exactly.

1 square inch = 4.03225×10⁻⁷ rai (Thai)

How to convert square inches to rai (Thai)

To convert square inches to rai (Thai), multiply the number of square inches by 4.03225×10⁻⁷. This factor is exact. To go the other way, multiply rai (Thai) by 2,480,004.96 (rounded).

rai (Thai) = square inches × 4.03225×10⁻⁷

Example: 10 square inches = 0.00000403225 rai (Thai).

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

Rai (Thai) (rai)

ThaiTraditional unit (still used in some regions)

Exactly 1,600 m² (about 0.4 acre). The standard unit of land in Thailand.

Rai is a Thai word for a field or plantation, and it is the standard unit for farmland and rural property in Thailand. One rai is the area of a square one sen on each side, which with a sen of 40 m gives 1,600 square meters, or 16 ares.

That is roughly 0.4 acre, so a hectare holds 6.25 rai. The rai is divided into 4 ngan and 400 square wa, and official land documents record areas in these three tiers, sometimes in shorthand such as 4-2-25 for 4 rai, 2 ngan and 25 square wa.

Older land measures in the region were looser, but the cadastral survey started in 1896 fixed the units against metric lengths. The rai is therefore exact today, and it is still the unit in which Thai land is bought, sold and taxed.

1 rai (Thai) = 1,600 square meters (exactly).

Sources: Wikipedia: Rai (unit); Wikipedia: Thai units of measurement

Related conversions

See all area units.