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Length Converter

Convert between metres, kilometres, centimetres, millimetres, miles, yards, feet and inches.

Length Converter

Professional grade conversion for length units.

Meter
Select Unit
0.001
Kilometer
Select Unit

Conversion Formula

1 Meter ≈ 0.001 Kilometer

What Length Converter does

Length is the conversion most people need most often, and it is one of the few where the imperial and metric systems are tied together by exact definitions rather than approximations.

Since 1959 the international yard has been defined as exactly 0.9144 metres, which makes the inch exactly 25.4 millimetres and the mile exactly 1609.344 metres. Conversions between the two systems are therefore precise, not rounded.

  • Metric: kilometre, metre, centimetre, millimetre
  • Imperial and US customary: mile, yard, foot, inch
  • Swap the direction without retyping the value

How to use Length Converter

  1. 1

    Enter the value

    Type the amount you want to convert. The result updates as you type.

  2. 2

    Select the units

    Choose what your value is in and what you want it in, for example centimetres to inches.

  3. 3

    Copy the result

    The copy button gives you the unformatted number, without thousands separators, ready to paste into a spreadsheet or code.

When to use it

Reading a specification from another country

Screen sizes, timber dimensions and paper sizes are quoted in different systems depending on where a product was made.

Buying materials

Convert a plan drawn in metres to the feet and inches a supplier quotes in.

Limits and known behaviour

  • The US survey foot, used in some American land surveying, is very slightly longer than the international foot and is not offered here. The difference is about two parts per million, which is irrelevant for everyday use and significant over survey distances.
  • Nautical miles, which are 1852 metres and used for sea and air navigation, are not included.
  • Displayed digits are a formatting choice, not a statement about the precision of your measurement.
  • Arithmetic uses double-precision floating point, so a converted value can end in a small representation residue. That is a property of binary arithmetic, not of the conversion factor.

Privacy and data handling

Runs entirely in your browser

  • The conversion is arithmetic performed in this page. Nothing you enter is transmitted or stored.
  • The tool works offline once the page has loaded.

Site-wide data handling, including analytics and advertising, is described in the privacy policy.

Frequently asked questions

Is the inch to centimetre conversion exact?

Yes. One inch is defined as exactly 2.54 centimetres by international agreement, so the conversion introduces no error at all.

How many significant figures should I keep?

No more than your original measurement had. Converting a wall measured to the nearest centimetre into inches with four decimal places implies a precision you did not measure.