Square Centimeters to Rai (Thai) (cm² to rai)

1 square centimeter equals 6.25×10⁻⁸ rai (Thai) exactly.

1 square centimeter = 6.25×10⁻⁸ rai (Thai)

How to convert square centimeters to rai (Thai)

To convert square centimeters to rai (Thai), multiply the number of square centimeters by 6.25×10⁻⁸. This factor is exact. To go the other way, multiply rai (Thai) by 16,000,000.

rai (Thai) = square centimeters × 6.25×10⁻⁸

Example: 10 square centimeters = 6.25×10⁻⁷ rai (Thai).

About these units

Square Centimeter (cm²)

Metric (SI)Current unit

A square one centimeter on a side; 1/10,000 of a square meter.

Physicists, rather than surveyors, put the centimeter at the center of a measuring system. Carl Friedrich Gauss proposed absolute units based on length, mass and time in 1832, choosing the millimeter, and in 1873 a British Association committee including James Clerk Maxwell and William Thomson (Lord Kelvin) recommended the centimeter, gram and second instead. In that CGS system the square centimeter turns up inside derived units, such as the stokes of kinematic viscosity, defined as one square centimeter per second.

A square centimeter is one ten-thousandth of a square meter, so 10,000 of them fill a square meter. It is a natural size for small flat things: a square inch is exactly 6.4516 cm², and a square foot is exactly 929.0304 cm². Because the CGS system defined force and pressure with the centimeter, the dyne per square centimeter became its unit of pressure, called the barye, which equals 0.1 pascal. SI practice prefers the square meter for large areas and the square millimeter for very small ones.

1 square centimeter = 0.0001 square meters (exactly).

Sources: Wikipedia: Centimetre-gram-second system of units; Wikipedia: Square centimetre; NIST Guide to the SI, Appendix B.8: conversion factors

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.