Roman Cubit (cubitum)

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

One and a half Roman feet, about 44.4 cm.

1 Roman cubit = 0.444 meters (approximately).

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

About the Roman cubit

Cubitum was the Latin word for elbow, and it came from a verb meaning to lie down or recline, the root of the English cubit. Roman writers such as Vitruvius defined it as one and a half Roman feet, or six palm widths, which gives about 444 mm. That is the figure used here. It was meant to span roughly the length of the forearm from the elbow to the fingertips.

Compared with other ancient cubits it was short. The Egyptian royal cubit survives on rods measuring about 523 to 529 mm, and Wikipedia says ancient cubits generally ranged from about 44.4 to 52.9 cm, so the Roman one sits at the bottom of that range. Romans also used a separate, longer ulna of about 120 cm. In a modern setting the Roman cubit is a little over 17 inches.

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

Roman Cubit conversion chart

1 Roman cubit expressed in every other length unit:

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