Millimeters to Toises (mm to toise)

1 millimeter equals 0.0005130740741 toises (rounded).

1 millimeter = 0.0005130740741 toises

How to convert millimeters to toises

To convert millimeters to toises, multiply the number of millimeters by 0.0005130740741. The factor is rounded to 10 significant digits. To go the other way, multiply toises by 1,949.03631 (rounded).

toises = millimeters × 0.0005130740741

Example: 10 millimeters = 0.005130740741 toises.

About these units

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

Toise (toise)

French (Ancien Régime)Historical unit (no longer in standard use)

Six pieds du roi, about 1.949 m. Used to define the length of the meter: the first metric standard was based on a ratio to the toise.

Latin tensa brachia, meaning outstretched arms, is the root of toise, and the unit began as a fathom-like span of a man's reach. Under the Ancien Régime it was fixed at six pieds du roi, 72 pouces or 864 lignes, which equals about 1.949 metres by the 1799 definition.

Its physical standard was an iron bar set into a wall of the Grand Châtelet in Paris, in place before 1394. After the bar bent, a replacement made in 1667 was about half a percent shorter. In 1735 two new geodetic standards were calibrated against it, and one of them, the Toise of Peru, took part in the Spanish-French Geodesic Mission and became the official standard in 1766.

The toise also shaped the metre. The 1799 metre was defined as 443.296 lignes, or 3 pieds and 11.296 lignes of the Toise of Peru, which matches 13,853 parts of 27,000 of a toise. Later French usage varied: from 1812 to 1840 the customary toise was set to exactly 2 metres, and other countries had their own toises, such as about 1.8 metres in Switzerland.

1 toise = 1.94903631 meters (approximately).

Sources: Wikipedia: Toise; Wikipedia: Pied du roi; Wikipedia: Traditional French units of measurement

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