Royal Cubits to Millimeters (cubit to mm)

1 royal cubit equals 525 millimeters exactly.

1 royal cubit = 525 millimeters

How to convert royal cubits to millimeters

To convert royal cubits to millimeters, multiply the number of royal cubits by 525. This factor is exact. To go the other way, multiply millimeters by 0.001904761905 (rounded).

millimeters = royal cubits × 525

Example: 10 royal cubits = 5,250 millimeters.

Approximate value. Standards for the royal cubit varied by place and period, so this converter uses the most commonly cited value. Treat results as estimates, not exact figures.

About these units

Royal Cubit (cubit)

Ancient EgyptianHistorical unit (no longer in standard use)Approximate value

The standard Egyptian cubit of about 52.5 cm (20.7 in), divided into 7 palms of 4 fingers. Surviving cubit rods were used to lay out the pyramids.

Among the earliest standard measures on record is the royal cubit, written meh niswt, meaning the cubit of the king. The English word cubit comes from Latin cubitum, the elbow, since the unit was first the forearm. The Egyptian version ran longer than the common cubit, holding seven palms of four fingers, or 28 fingers, against 24 for the ordinary one. It appears in Old Kingdom building work from at least the Step Pyramid of Djoser, around 2700 BC.

Our knowledge of its size comes from physical rods. Richard Lepsius compared fourteen of them in 1865, and examples from the tombs of Maya at Saqqara and Kha at Thebes survive, one folding rod being in the Museo Egizio in Turin. Measured rods fall between about 523.5 and 529.2 mm, so the 52.5 cm used here is one common estimate within that range. In modern terms the cubit is roughly 20.6 to 20.8 inches, a little over half a metre.

1 royal cubit = 0.525 meters (approximately).

Sources: Wikipedia: Cubit; Wikipedia: Ancient Egyptian units of measurement

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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