Leagues to Millimeters (lea to mm)

1 league equals 4,828,032 millimeters exactly.

1 league = 4,828,032 millimeters

How to convert leagues to millimeters

To convert leagues to millimeters, multiply the number of leagues by 4,828,032. This factor is exact. To go the other way, multiply millimeters by 2.071237307×10⁻⁷ (rounded).

millimeters = leagues × 4,828,032

Example: 10 leagues = 48,280,320 millimeters.

About these units

League (lea)

US & ImperialHistorical unit (no longer in standard use)

Three statute miles (4.828 km). Said to be roughly the distance a person could walk in an hour; the length varied widely across Europe.

How far can a person walk in an hour? Roughly that question lies behind the league, which may once have approximated the answer. The Romans borrowed the idea from Gaul, calling it the leuga Gallica and fixing it at one and a half Roman miles, about 2.2 km. The word survives in several languages, yet the length it names has been anything from about 2.2 km to nearly 7.9 km depending on the country and the century.

In England the land league was most often three statute miles, which gives 4.83 km, or exactly 4,828.032 m, the figure used here. A medieval chronicle from Battle Abbey instead defined the English leuga as 7,680 feet. French lieues ranged from about 3.25 to 4.68 km, and a metric lieue of 4,000 m was legal from 1812 to 1840. The Spanish legua of about 5.57 km lasted in Latin America, where it also measured land area in early grants in Texas and New Mexico. No country defines it officially today.

1 league = 4,828.032 meters (exactly).

Sources: Wikipedia: League (unit); Wikipedia: Mile

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

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