Sen (Thai) to Meters (sen to m)

1 sen (Thai) equals 40 meters exactly.

1 sen (Thai) = 40 meters

How to convert sen (Thai) to meters

To convert sen (Thai) to meters, multiply the number of sen (Thai) by 40. This factor is exact. To go the other way, multiply meters by 0.025.

meters = sen (Thai) × 40

Example: 10 sen (Thai) = 400 meters.

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)

Meter (m)

Metric (SI)Current unit

The SI base unit of length. Since 1983 it is defined as the distance light travels in a vacuum in 1/299,792,458 of a second.

Meter comes from the Greek metron, a measure. In 1791 the French National Assembly defined it as one ten-millionth of the distance from the equator to the North Pole along a great circle through Paris, after rejecting the length of a seconds pendulum because that length changes with local gravity. The surveyors Delambre and Méchain measured the meridian arc, and in 1799 a platinum bar known as the Mètre des Archives became the physical standard. NIST notes that this Earth-based meter turned out to be about 0.2 mm shorter than the true pole-to-equator fraction it was meant to represent.

The 1875 Treaty of the Meter created the CGPM and the BIPM to look after common standards, and in 1889 a platinum-iridium prototype bar took over; the original is still kept at the BIPM. In 1960 the meter was tied to 1,650,763.73 wavelengths of an orange-red krypton-86 line, and in 1983 to the speed of light, which made length a quantity derived from the time standard. The 2018 revision reworded that definition without changing the meter's size. NIST offers a handy yardstick for scale: a pace, meaning two steps, is roughly a meter or a yard.

The meter is the reference unit for length on this site.

Sources: BIPM: history of the metre; NIST: the meter and the SI redefinition; Wikipedia: Metre

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