US Survey Miles to Millimeters (mi (US) to mm)

1 US survey mile equals 1,609,347.219 millimeters (rounded).

1 US survey mile = 1,609,347.219 millimeters

How to convert US survey miles to millimeters

To convert US survey miles to millimeters, multiply the number of US survey miles by 1,609,347.219. The factor is rounded to 10 significant digits. To go the other way, multiply millimeters by 6.213699495×10⁻⁷ (rounded).

millimeters = US survey miles × 1,609,347.219

Example: 10 US survey miles = 16,093,472.19 millimeters.

About these units

US Survey Mile (mi (US))

US land surveyHistorical unit (no longer in standard use)

5,280 US survey feet (about 1,609.347 m). Slightly longer than the international mile, used in US land surveys until 2022.

Because it is built from 5,280 survey feet, this mile inherits the survey foot's tiny excess and comes to about 1,609.347 m, against exactly 1,609.344 m for the international mile. The gap is under 1/8 inch, or 3.2 mm, per mile, and one international mile equals 0.999998 survey miles. In US law the formal statute mile was the survey mile, though everyday usage treats the two as the same.

Over a single trip the difference vanishes, but State Plane Coordinate Systems can stretch across hundreds of miles, where a few millimetres per mile accumulate into something a surveyor must account for. For that reason surveyors kept the survey mile long after the international foot took over elsewhere. In October 2019 the National Geodetic Survey and NIST announced that the survey foot and mile would be retired from 1 January 2023, and NIST says the unit now survives only for historic and legacy data. Maps and deeds written before then still use it.

1 US survey mile = 1,609.347219 meters (approximately).

Sources: Wikipedia: Mile; NIST: U.S. survey foot

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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