Millimeters to Hands (mm to hh)

1 millimeter equals 0.009842519685 hands (rounded).

1 millimeter = 0.009842519685 hands

How to convert millimeters to hands

To convert millimeters to hands, multiply the number of millimeters by 0.009842519685. The factor is rounded to 10 significant digits. To go the other way, multiply hands by 101.6.

hands = millimeters × 0.009842519685

Example: 10 millimeters = 0.09842519685 hands.

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

Hand (hh)

US & ImperialTraditional unit (still used in some regions)

Exactly 4 inches (10.16 cm). Used almost only to measure the height of horses at the withers.

Horse people still say a mare stands fifteen hands, and the word is the same Old English hand that names the body part. The unit was first the breadth of a hand, with or without the thumb, or the height of a clenched fist, and the figure varied from person to person. Ancient Egyptian cubit-rods show a comparable hand of five digits, roughly 94 mm. In England, a Horses Act of 1540 under Henry VIII fixed the hand at four inches, and some later dictionaries still muddled it with the three-inch handsbreadth.

The figure used here is exactly 4 inches, or 10.16 cm. Fractions are counted in inches, not tenths, so a height written 15.2 means fifteen hands and two inches, which is 62 inches, and 15.3 is followed directly by 16.0. The height is taken at the withers, the ridge between the shoulder blades. The unit survives for horses and ponies in the United States, Canada, the United Kingdom, Ireland, Australia and New Zealand, while continental Europe and international equestrian competition use metric.

1 hand = 0.1016 meters (exactly).

Sources: Wikipedia: Hand (unit); Wiktionary: hand

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