# Calculations

## Length Converter

How much is one inch in cm?

What is an astronomic unit?

How do I convert one mile into kilometre?

Here, the lengths in different scales can be converted.

Just enter the value, unit and confirm using 'OK '.

Metric: | 1 | m | metre |

0.001 | km | kilometre | |

100 | cm | centimetre | |

1000 | mm | millimetre | |

Anglo-American: | 39.37 | in | inch |

3.281 | ft | Foot | |

1.094 | yd | yard | |

621.371⋅10^{-6} | stat.mi. | mile | |

Nautic: | 539.957⋅10^{-6} | NM | nautic mile |

Astronomical | 6.685⋅10^{-12} | AU | astronomic unit |

105.7⋅10^{-18} | ly | light year | |

32.408⋅10^{-18} | pc | parsec |

## Length definition:

**Metric system:** The metric system was introduced in France in the 9th decade of the 18th century. The basic unit, the metre, should represent the tenmillionth part of the distance between the pole and the equator. Today the metre is defined like all the SI-units by a natural constant, the speed of light.

**Anglo-American system:** This system, also called U.S. Custom system, evolved from the English system, which uses typical lengths of body parts as basic units. Today it is used frequently in the U.S.

It is: 1 in = 1/12 ft = 1/36 yd = 0.025 m

**Nautic system:** in shipping the length are given in nautic miles (NM). One nautic mile was originally defined as the distance a ship covers if it changes its position by one angular minute (1/60 degree). Today, the nautical mile is set at 1852 m.

**Astronomic system:** To specify lengths in astronomy in concise scales different units were introduced: The Astronomic Unit (AU), corresponding to the distance between earth and sun, amounts to 149 597 870 691 m. The light year (ly) is the distance light travels within one year. It is: 1 ly = 9 460 730 472 580 800 m. One parsec (pc) is defined as the distance of a point which builds a rectangular triangle with sun and earth, that has an angle of one angular second.