Megaparsecs to Kilometers (Mpc to km)

1 megaparsec equals 3.085677581×10¹⁹ kilometers (rounded).

1 megaparsec = 3.085677581×10¹⁹ kilometers

How to convert megaparsecs to kilometers

To convert megaparsecs to kilometers, multiply the number of megaparsecs by 3.085677581×10¹⁹. The factor is rounded to 10 significant digits. To go the other way, multiply kilometers by 3.240779289×10⁻²⁰ (rounded).

kilometers = megaparsecs × 3.085677581×10¹⁹

Example: 10 megaparsecs = 3.085677581×10²⁰ kilometers.

About these units

Megaparsec (Mpc)

AstronomicalCurrent unit

One million parsecs (about 3.26 million light-years). Used for distances between galaxies.

Galaxies are too far apart for the parsec to be comfortable, so astronomers multiply it by a million. A megaparsec, symbol Mpc, is 1,000,000 parsecs, or roughly 3.26 million light-years and about 3.09 times ten to the twenty-second power meters. It has no article of its own on Wikipedia and is treated as one of the parsec's multiples, alongside the kiloparsec for distances inside a galaxy and the gigaparsec for the largest cosmic structures.

Neighboring galaxies sit at a fraction of a megaparsec: the Andromeda Galaxy is about 0.78 Mpc away, while the Virgo Cluster lies near 16.5 Mpc. Cosmologists also use the unit inside the Hubble constant, quoted in kilometers per second per megaparsec, which expresses how fast distant galaxies recede for each megaparsec of separation. The Milky Way itself is roughly 34 kiloparsecs across, a useful reminder of how much larger intergalactic distances are.

1 megaparsec = 3.085677581×10²² meters (approximately).

Sources: Wikipedia: Parsec; Wikipedia: Megaparsec (redirects to Parsec)

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

Related conversions

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