Convert millimeters to kilometers
Converting millimeters to kilometers is a common length task, whether you are checking a recipe, a spec sheet, a travel distance or a homework problem. Since 1 mm equals 0.000001 km, the math is a single multiplication — and this page does it for you instantly, with the formula, a table of common values and answers to the questions people ask most.
Exact factor
How to convert millimeters to kilometers
To convert millimeters to kilometers, multiply the number of millimeters by 0.000001. For example, 10 mm × 0.000001 = 0.00001 km.
km = mm × 0.000001
- Write down the value in millimeters you want to convert.
- Multiply it by 0.000001 (the exact mm→km factor).
- The result is your value in kilometers. Check it below with the converter or the table.
Conversion table
Common values of millimeters and their equivalents in kilometers:
| mm | km |
|---|---|
| 1 | 0.000001 |
| 2 | 0.000002 |
| 3 | 0.000003 |
| 4 | 0.000004 |
| 5 | 0.000005 |
| 10 | 0.00001 |
| 20 | 0.00002 |
| 25 | 0.000025 |
| 50 | 0.00005 |
| 100 | 0.0001 |
| 250 | 0.00025 |
| 500 | 0.0005 |
About these units
Millimeter (mm). A millimeter is one thousandth of a meter, the smallest length unit in everyday metric use. It is the standard precision unit in engineering drawings, machining and rainfall measurement.
Kilometer (km). A kilometer equals 1,000 meters and is the standard metric unit for road distances and geography. One kilometer is about 0.62 miles or a 12-minute walk.
Frequently asked questions
How do I convert millimeters to kilometers?
To convert millimeters to kilometers, multiply the number of millimeters by 0.000001. For example, 10 mm × 0.000001 = 0.00001 km. Or skip the math: type the value into the converter at the top of this page and the result updates instantly.
How many kilometers are in 1 millimeter?
1 mm = 0.000001 km. That is the fixed relationship used by this converter and by international standards.
How many millimeters are in 1 kilometer?
1 km = 1,000,000 mm. If you are converting in the opposite direction, use our Kilometer to Millimeter converter for the dedicated table and FAQ.
Is the millimeters to kilometers conversion exact?
Yes. Both units are defined by international agreement, so the factor of 0.000001 is exact. Displayed results are rounded to 6 significant digits only for readability.
What is millimeter used for?
A millimeter is one thousandth of a meter, the smallest length unit in everyday metric use. It is the standard precision unit in engineering drawings, machining and rainfall measurement.