Thou to Kilometers (thou to km)

1 thou equals 2.54×10⁻⁸ kilometers exactly.

1 thou = 2.54×10⁻⁸ kilometers

How to convert thou to kilometers

To convert thou to kilometers, multiply the number of thou by 2.54×10⁻⁸. This factor is exact. To go the other way, multiply kilometers by 39,370,078.74 (rounded).

kilometers = thou × 2.54×10⁻⁸

Example: 10 thou = 2.54×10⁻⁷ kilometers.

About these units

Thou (thou)

US & ImperialCurrent unit

One thousandth of an inch (0.0254 mm), also called a mil. Used in machining, plastics and the thickness of films and wire.

Machinists say a part is out by a few thou, and the word is a clipping of thousandth, keeping only the first syllable. In North America the same length is often called a mil, which is easy to confuse with a millimetre in international drawings. One thou is a thousandth of an inch, which is exactly 0.0254 mm or 25.4 micrometres, so about 39 of them fit in a millimetre. The word is both singular and plural.

Joseph Whitworth pressed in 1857 for engineers to think in decimal thousandths instead of fractions of an inch, a habit that needed vernier calipers and micrometers to put into practice. Today the unit describes the thickness of paper, foil, wire, plastic sheet and paint films, with a plastic ID card about 30 thou thick. It also appears in older spark-plug gaps, gasket thicknesses and circuit-board geometry. For finer work, a tenth, meaning 0.0001 inch or 2.54 micrometres, is common, and gauge blocks are often given in millionths or in micrometres.

1 thou = 0.0000254 meters (exactly).

Sources: Wikipedia: Thou (unit); Wiktionary: thou

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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