Millimeters to Barleycorns (mm to bc)

1 millimeter equals 0.1181102362 barleycorns (rounded).

1 millimeter = 0.1181102362 barleycorns

How to convert millimeters to barleycorns

To convert millimeters to barleycorns, multiply the number of millimeters by 0.1181102362. The factor is rounded to 10 significant digits. To go the other way, multiply barleycorns by 8.466666667 (rounded).

barleycorns = millimeters × 0.1181102362

Example: 10 millimeters = 1.181102362 barleycorns.

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

Barleycorn (bc)

Medieval EnglishHistorical unit (no longer in standard use)

One third of an inch. A medieval English unit defined as the length of a grain of barley; the origin of the shoe-size increment.

Three dry, round grains of barley laid end to end made an inch, according to an English statute known as the Composition of Yards and Perches, dated about 1300. The idea is older still, since the Welsh Laws of Hywel Dda in the 10th century used a similar rule. A barleycorn is therefore one third of an inch, about 8.47 mm, although Wikipedia's infobox rounds it to 8.46 mm. Wiktionary describes the word simply as a compound of barley and corn, meaning grain.

Real barley kernels range from roughly 4 to 15 mm depending on the cultivar, and older sources put the average near 8.8 mm, so the grain gave a notion of size, not a precise standard. Formal standards were later set by comparison with a reference yard bar, with the barleycorn taken as 1/108 of its length. A line is a quarter of a barleycorn and a poppyseed a quarter or fifth. The unit lives on mainly in shoe sizing in some English-speaking countries, where each size step is one barleycorn.

1 barleycorn = 0.008466666667 meters (approximately).

Sources: Wikipedia: Barleycorn (unit); Wiktionary: barleycorn

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