Cubits to Inches (cbt to in)

1 cubit equals 18 inches exactly.

1 cubit = 18 inches

How to convert cubits to inches

To convert cubits to inches, multiply the number of cubits by 18. This factor is exact. To go the other way, multiply inches by 0.05555555556 (rounded).

inches = cubits × 18

Example: 10 cubits = 180 inches.

Approximate value. Standards for the 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

Cubit (cbt)

Medieval EnglishHistorical unit (no longer in standard use)Approximate value

Traditionally the length from the elbow to the tip of the middle finger. The common English cubit is taken as 18 inches (45.72 cm); ancient cubits ranged from about 44 to 53 cm.

From the Latin cubitum, meaning elbow, the cubit was the forearm measured from the elbow to the fingertips. English use tied it to roughly 18 inches, or 45.72 cm. Such a hand-and-arm measure is the same idea that produced the ell, which Wikipedia describes as originally a cubit.

No single value ever governed it. Wikipedia lists most ancient cubits between 44.4 and 52.92 cm, from the Roman cubitus of about 444 mm, which Vitruvius set at one and a half Roman feet, to the Egyptian royal cubit near 523 to 529 mm. Medieval Islamic cubits ranged far wider still.

The English ell eventually settled at 45 inches, one and a quarter yards, while the cubit faded from commerce. A trace survives in hedgelaying, where a forearm of about 18 inches sets the spacing of stakes. The figure used here is the 18 inch English cubit.

1 cubit = 0.4572 meters (approximately).

Sources: Wikipedia: Cubit; Wikipedia: Ell

Inch (in)

US & ImperialCurrent unit

1/12 of a foot. Defined as exactly 25.4 millimeters since 1959, when the US and Commonwealth countries agreed a common international inch.

Latin uncia, meaning one-twelfth, is the root of both inch and ounce, and it passed into Old English as ynce. Roman measurers divided their foot into twelve unciae, and the English inch kept that twelfth. After 1066 an inch was reckoned as three barleycorns, and a 1324 statute attributed to Edward II spelled out the definition as three grains of barley, dry and round, placed end to end lengthwise. For centuries the inch was simply a twelfth of a foot, or a thirty-sixth of a yard, and the US and UK each kept their own copy of the standard yard.

Those copies differed slightly until the 1959 international agreement fixed the yard at exactly 0.9144 meter, which made the inch exactly 25.4 millimeters. The US adopted it in 1959 and the UK ratified it in 1963, effective 1964. Today the inch is still the customary unit in the United States and Canada, and the UK keeps it on road signs. Worldwide it also names display diagonals, wheel rims, tire codes and pipe sizes.

1 inch = 0.0254 meters (exactly).

Sources: Wikipedia: Inch; Wikipedia: Yard; NIST Guide to the SI, Appendix B.8: conversion factors

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