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Millimeters to Kilometers (mm to km) Converter

1 millimeter (mm) = 0.000001 kilometers (km). To convert millimeters to kilometers, multiply by 0.000001: 297 mm × 0.000001 = 0.000297 km. Also searched as millimetres to kilometres.

1 mm = 0.000001 km
Convert the other way: Kilometers to Millimeters

Quick facts

How to convert millimeters to kilometers

  1. Take the value in millimeters.
  2. Multiply it by 0.000001 (the number of kilometers in one millimeter).
  3. Round the result to the precision you need.
km = mm × 0.000001

Worked example (the long side of an A4 sheet): 297 mm × 0.000001 = 0.000297 km.

To convert kilometers back to millimeters, multiply by 1,000,000, or divide by 0.000001.

Source: NIST Special Publication 811 (2008), Appendix B; the international yard and pound agreement of 1959 (1 inch = 25.4 mm exactly).

Millimeters to Kilometers conversion table

Millimeters to Kilometers conversion table
Millimeters [mm]Kilometers [km]
1 mm0.000001 km
10 mm0.00001 km
100 mm0.0001 km
1000 mm0.001 km
10000 mm0.01 km
100000 mm0.1 km
1000000 mm1 km

mm to km chart from 1 to 100

Kilometers to Millimeters conversion table

Kilometers to Millimeters conversion table
Kilometers [km]Millimeters [mm]
0.001 km1000 mm
0.01 km10000 mm
0.1 km100000 mm
0.5 km500000 mm
1 km1000000 mm
2 km2000000 mm
5 km5000000 mm
10 km10000000 mm

Millimeters vs Kilometers

MillimeterKilometer
Symbolmmkm
Equals1 mm = 0.000001 km1 km = 1,000,000 mm

What is a millimeter?

One thousandth of a meter, the SI base unit of length. Used for small, precise measurements in engineering, printing, and manufacturing tolerances.

What is a kilometer?

One thousand meters. Used for road distances and geography in every country except the US, UK, and Myanmar.

Frequently asked questions

How many kilometers are in a millimeter?

There are 0.000001 kilometers in 1 millimeter (1 mm = 0.000001 km).

How many millimeters are in a kilometer?

There are 1,000,000 millimeters in 1 kilometer (1 km = 1000000 mm).

How do I convert millimeters to kilometers?

Multiply the number of millimeters by 0.000001. For example, 10 mm × 0.000001 = 0.00001 km. To convert back, multiply by 1,000,000.

What is 10 mm in kilometers?

10 mm = 0.00001 km.

What is 100 mm in kilometers?

100 mm = 0.0001 km.

Is the conversion exact?

Yes. The factor comes from the official definitions of both units (NIST Special Publication 811 (2008), Appendix B; the international yard and pound agreement of 1959 (1 inch = 25.4 mm exactly)). Results are shown to up to 10 decimal places; round them to suit your purpose.

Popular length conversions

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Reviewed by

Dr. Muhammad Amjad Khadim PhD Mathematics

Dr. Muhammad Amjad Khadim holds a PhD in Mathematics. He writes and reviews the guides on pakmath.com and checks every formula, conversion factor and worked example against published standards and official guidance before it goes live. Spotted an error? Tell us and it will be corrected.

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First published 28 October 2026 · Last reviewed 5 November 2026