For the unit of information, see qubit

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Cubit is the name for the ancient Egyptian and Sumerian units of measure.

These Cubits are among the first recorded units of length used by an ancient people. From around 1950 BC, the copper bar cubit of Nippur defines the Sumerian cubit as 517.2 mm (20.36 inches) and is the earliest known length standard.

While no standard rule exists from Old Kingdom Egypt, it has been securely estabished from surviving architectural evidence that a standard measure was employed as early as c. 2750 BC at Saqqara. From the evidence this is widely accepted to have been 523.5 to 524 mm (20.61 to 20.63 in) in length, and was subdivided into 7 palms of 4 digits, giving a 28 part measure in total. A shorter rule of 6 palms may also have been employed, but based on the same 7 part standard. The basic length was probably originally based on the length of the forearm from the elbow to the middle finger tip. Standard Egyptian Cubits survive from later dynasties.

See also

• Ancient weights and measures

eo:ulno fr:Coudée sl:vatel

There is both a shorter version and a longer version of the cubit. The short version is measured from the elbow to the knuckles on a clenched fist. The larger version of a Cubit was 51.8 cm (20.4 in).