Sen (Thai) to Millimeters (sen to mm)

1 sen (Thai) equals 40,000 millimeters exactly.

1 sen (Thai) = 40,000 millimeters

How to convert sen (Thai) to millimeters

To convert sen (Thai) to millimeters, multiply the number of sen (Thai) by 40,000. This factor is exact. To go the other way, multiply millimeters by 0.000025.

millimeters = sen (Thai) × 40,000

Example: 10 sen (Thai) = 400,000 millimeters.

About these units

Sen (Thai) (sen)

ThaiTraditional unit (still used in some regions)

20 wa, exactly 40 meters. A traditional Thai unit of distance, rarely used now except in rural areas.

Sen, a word that also means a rope or line, names a Thai distance of 20 wa. In metric terms that is 40 meters, a round figure that surveyors of the late nineteenth century found convenient for map scales.

The Royal Thai Survey Department began its cadastral survey in 1896, and its director, R. W. Giblin, noted that 40 m, or 4,000 cm, make one sen, so plans could be drawn at 1:4,000. A square with sides of one sen is the rai, which is why the sen sits at the center of the Thai land system.

Above it, 400 sen make one yot, a long travel distance of 16 km, and below it come the wa, sok and khuep. Day to day the sen has largely given way to meters and kilometers, though it survives in rural speech and in the definition of the rai.

1 sen (Thai) = 40 meters (exactly).

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

Millimeter (mm)

Metric (SI)Current unit

One thousandth of a meter. Used in engineering, manufacturing and rainfall measurement.

Carl Friedrich Gauss put the millimeter at the base of his 1832 proposal for absolute units, pairing it with the milligram and the second, although the centimeter-based CGS system later won out among scientists. The name combines the metric prefix milli-, from the Latin for one thousand, with the meter. Since 1983 a millimeter has been tied to the speed of light: it is the distance light covers in 1/299,792,458,000 of a second.

Millimeters are the language of fine mechanical work. Standard rulers are divided into them, digital calipers commonly read to 0.01 mm, and mechanical pencil leads come in 0.5 and 0.7 mm. Copy paper is about 0.1 mm thick, and a thin hair, at 0.02 to 0.04 mm across, is close to the smallest thing the naked eye can see. A wave with a frequency of 300 GHz has a wavelength of 1 mm. An inch is exactly 25.4 mm. One trap for readers in the United States is that mil there traditionally means a thousandth of an inch, not a millimeter.

1 millimeter = 0.001 meters (exactly).

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

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