Millimeters to Rods (mm to rd)

1 millimeter equals 0.0001988387815 rods (rounded).

1 millimeter = 0.0001988387815 rods

How to convert millimeters to rods

To convert millimeters to rods, multiply the number of millimeters by 0.0001988387815. The factor is rounded to 10 significant digits. To go the other way, multiply rods by 5,029.2.

rods = millimeters × 0.0001988387815

Example: 10 millimeters = 0.001988387815 rods.

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

Rod (rd)

US & ImperialTraditional unit (still used in some regions)

16.5 feet or 5.5 yards (5.0292 m), also called a pole or perch. A quarter of a chain; a basic unit of English land measurement.

Three names, rod, pole and perch, all describe the same stick. Perch comes from the Roman pertica, a ten-foot measuring pole of about 2.96 m, while rod and pole name the physical staff that farmers and surveyors carried. A statute from around the thirteenth or fourteenth century defined the perch as five and a half ells. In the thirteenth century English perches ranged from 18 to 24 feet, and a parliamentary report of 1820 still found lengths between 16.5 and 25 feet in local use.

The version that won out is 16.5 feet, or 5.5 yards, exactly 5.0292 m, which is the figure used here. It is a quarter of a chain, 40 to a furlong and 320 to a mile, and 160 square rods make an acre. Ireland kept a longer perch of 21 feet. The rod faded from legal use in the UK with metrication from 1965, but allotments are still measured in square poles, canoeists count portages in rods, and pipeline easements and US property descriptions still use it.

1 rod = 5.0292 meters (exactly).

Sources: Wikipedia: Rod (unit); NIST SP 811, Appendix B.8 (length conversion factors)

Related conversions

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