Feet to Roman Inches (ft to uncia)

1 foot equals 12.3902439 Roman inches (rounded).

1 foot = 12.3902439 Roman inches

How to convert feet to Roman inches

To convert feet to Roman inches, multiply the number of feet by 12.3902439. The factor is rounded to 10 significant digits. To go the other way, multiply Roman inches by 0.08070866142 (rounded).

Roman inches = feet × 12.3902439

Example: 10 feet = 123.902439 Roman inches.

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

About these units

Foot (ft)

US & ImperialCurrent unit

12 inches. Defined as exactly 0.3048 meters. Still the standard unit for height, altitude in aviation and room dimensions in the US and UK.

Human anatomy supplied the idea: an adult foot is roughly 15 percent of body height. Ancient cultures turned that into standards, but not the same one. The Greek pous was about 302 mm, the standard Roman pes about 295.7 mm, and a Harappan foot of about 335 mm has been reported from the Indus Valley. Historically, a foot fell somewhere between about 250 and 335 mm. Charlemagne tried to standardize units around 790 with little lasting success, and in 1593 English law fixed the statute mile at 5,280 feet.

The modern foot dates from the 1959 International Yard and Pound Agreement, which defined the yard as exactly 0.9144 meter and so the foot as exactly 0.3048 meter; the UK adopted it on 1 January 1964. The US survey foot, defined in 1893 as 1200/3937 meter, was deprecated on 31 December 2022. Feet remain in everyday use for height and rooms in the US, and ISO shipping containers are defined in them. Aviation altitudes use them too: flight level 330 means 33,000 feet.

1 foot = 0.3048 meters (exactly).

Sources: Wikipedia: Foot (unit); Wikipedia: Mile; NIST Guide to the SI, Appendix B.8: conversion factors

Roman Inch (uncia) (uncia)

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

One twelfth of a Roman foot, about 2.46 cm. Its name, uncia, is the root of the English words 'inch' and 'ounce'.

Twelve of these made up a Roman foot, and that fraction is the whole meaning of the name: uncia is Latin for a twelfth. The same word was applied to weight, where it gave the ounce as a twelfth of the Roman pound. Because the foot is about 296 mm, the uncia works out to roughly 24.6 mm, the value Wikipedia gives, though that article notes the figure lacks a citation. Any difference in the foot carries straight through to its inch.

Latin also had pollex, meaning thumb, as a synonym for the length. Old English borrowed uncia as ynce, and a regular sound change turned it into the modern word inch, which is a cousin of ounce. The English inch kept the idea of a twelfth of a foot but was later fixed by international agreement at exactly 25.4 mm, so it is about 3 percent larger than the Roman original.

1 Roman inch (uncia) = 0.0246 meters (approximately).

Sources: Wikipedia: Roman inch; Wikipedia: Inch; Wikipedia: Ancient Roman units of measurement

Related conversions

See all length units.