Millimeters to Sun (mm to sun)

1 millimeter equals 0.033 sun exactly.

1 millimeter = 0.033 sun

How to convert millimeters to sun

To convert millimeters to sun, multiply the number of millimeters by 0.033. This factor is exact. To go the other way, multiply sun by 30.3030303 (rounded).

sun = millimeters × 0.033

Example: 10 millimeters = 0.33 sun.

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

Sun (sun)

JapaneseTraditional unit (still used in some regions)

One tenth of a shaku, about 3.03 cm. The Japanese 'inch', still used in carpentry.

Sun is the Japanese reading of the Chinese character for cun, the Chinese inch, which was traditionally the width of a person's thumb at the knuckle. Japan took the whole system over from China, and the sun kept its place as one tenth of the foot-like shaku.

Because the shaku was fixed in 1891 at 10/33 meter, the sun works out to 1/33 meter, about 30.3 millimeters or 1.19 inches. That makes it about 19 percent longer than a modern inch. Before the legal definition, the size drifted slightly between eras and regions, so older measurements in sun carry some uncertainty.

Smaller steps below it, such as the bu, divide it further. Today the sun survives mainly in carpentry, joinery and traditional crafts, where dimensions are still quoted in shaku and sun before being translated into the millimeters on modern rulers.

1 sun = 0.0303030303 meters (approximately).

Sources: Wikipedia: Cun (unit); Wikipedia: Shaku (unit); Wikipedia: Japanese units of measurement

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