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Metric length unit converter

Convert a length between every unit of the metric system —myriametre, kilometre, hectometre, decametre, metre, decimetre, centimetre and millimetre— and also to micrometre, nanometre, ångström and light-year. Below the result you'll see the amount expressed in every unit at once.

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Metre

1000 m

Equivalents

Light-year1.057000834e-13 ly
Myriametre0.1 mam
Kilometre1 km
Hectometre10 hm
Decametre100 dam
Metre1000 m
Decimetre10000 dm
Centimetre100000 cm
Millimetre1000000 mm
Micrometre1000000000 µm
Nanometre1000000000000 nm
Ångström10000000000000 Å

Each metric unit is 10 times the next one, so converting means moving the decimal point. The tool converts the value to metres and then to the target unit:

  • 1 mam = 10 km = 10,000 m
  • 1 m = 10 dm = 100 cm = 1000 mm
  • 1 mm = 1000 µm; 1 µm = 1000 nm; 1 nm = 10 Å
  • 1 light-year = 9,460,730,472,580,800 m (IAU definition: a Julian year of 365.25 days at the speed of light)

Use cases

  • Solving school exercises on length unit conversion.
  • Expressing cell, virus or wavelength sizes in µm or nm.
  • Getting a feel for astronomical distances in light-years.

How it works

  1. 1

    Type the amount

    Decimals with a dot or a comma are accepted, as are negative values.

  2. 2

    Pick the units

    Choose the source and target units; the result and the equivalents table update instantly.

Technical details

  • The myriametre (10 km) is no longer part of the SI, but it's still taught as part of the metric prefix ladder.
  • The ångström (0.1 nm) isn't an SI unit either; it's used in crystallography and atomic physics.
  • Results use 10 significant figures; very large or very small values are shown in scientific notation (e.g. 1e-10).

Frequently asked questions

How many metres are in a kilometre?

1000 metres. Each step on the ladder (km, hm, dam, m) multiplies or divides by 10.

Is a light-year a unit of time?

No, it's a length: the distance light travels in a vacuum during one Julian year, about 9.46 trillion kilometres.

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