Roman Inches to Kilometers (uncia to km)

1 Roman inch (uncia) equals 0.0000246 kilometers exactly.

1 Roman inch (uncia) = 0.0000246 kilometers

How to convert Roman inches to kilometers

To convert Roman inches to kilometers, multiply the number of Roman inches by 0.0000246. This factor is exact. To go the other way, multiply kilometers by 40,650.4065 (rounded).

kilometers = Roman inches × 0.0000246

Example: 10 Roman inches = 0.000246 kilometers.

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

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

Kilometer (km)

Metric (SI)Current unit

1,000 meters. The standard unit for road distances in most countries.

A name for 1,000 meters took a while to settle. In 1793 France's National Convention made the metre the sole French unit of length, and the first proposed name for the thousand-metre multiple was millaire. Everyday French usage then leaned on the myriametre, 10,000 meters, well into the 1800s. The Netherlands adopted the kilometre in 1817, under the local name mijl, and made it the only official unit of that size in 1867. In 1935 the CIPM dropped the myria- prefix, which left the kilometre as the standard unit for road-scale distances.

Kilo- is the SI prefix for a thousand, and the kilometre is now the preferred unit for land distances in most of the world, with the United States, the United Kingdom and Liberia among those that still use the mile. One kilometre is about 0.621 mile. The main span of Lisbon's 25 de Abril Bridge, at 1.013 km, gives a sense of the scale. Even its pronunciation has been argued over: in 1970 Australia's Metric Conversion Board made stress on the first syllable official, although Prime Minister Gough Whitlam argued for stress on the second. Military slang in several countries calls it a klick.

1 kilometer = 1,000 meters (exactly).

Sources: Wikipedia: Kilometre; Wikipedia: Metric prefix; BIPM: history of the metre

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