Convert Kilometers to millimeters

1 kilometer = 1,000,000 millimeters · mm = km × 1,000,000

km
Millimeters
1,000,000mm

1 kilometer = 1,000,000 millimeters

When you need this conversion

This conversion goes from kilometers, the metric unit for road distances and travel, to millimeters, the metric unit used for hardware, engineering drawings, and anything needing sub-centimeter precision. Both measure the same physical quantity, so the conversion is exact — the difference is which unit your source, tool, or region happens to use.

Kilometers to millimeters conversion table

Conversion table from kilometers to millimeters
Kilometers (km)Millimeters (mm)
1 km1,000,000 mm
2 km2,000,000 mm
3 km3,000,000 mm
5 km5,000,000 mm
10 km10,000,000 mm
15 km15,000,000 mm
20 km20,000,000 mm
25 km25,000,000 mm
50 km50,000,000 mm
75 km75,000,000 mm
100 km100,000,000 mm
250 km250,000,000 mm
500 km500,000,000 mm
1,000 km1,000,000,000 mm

The formula

mm = km × 1,000,000

Because both units measure length, the conversion is a single multiplication by a fixed factor. That factor never changes, so the result is exact.

Convert the other way

Millimeters to kilometers →

Related length conversions

All length conversions →

Frequently asked questions

How many millimeters are in a kilometer?
There are 1,000,000 millimeters in 1 kilometer. The formula is mm = km × 1,000,000.
How do you convert kilometers to millimeters?
Use the formula mm = km × 1,000,000. For example, 10 kilometers equals 10,000,000 millimeters.
Is the kilometers to millimeters conversion exact?
Yes. Kilometers and millimeters are both units of length, related by an exact defined factor. Displayed results are rounded for readability.
What is km short for?
km is the standard symbol for kilometer (also written as kilometres). mm is the symbol for millimeter.