Kilometres to Millimetres
Convert kilometres to millimetres (km to mm). 1 km = 1,000,000 mm. Use the calculator, formula and conversion table.
How to convert kilometres to millimetres
Multiply the amount in kilometres by 1,000,000 to get millimetres. The displayed factor and results are rounded to 12 significant digits.
mm = km × 1,000,000Worked example
1 km = 1,000,000 mm. Change the amount in the calculator above to use your own value.
Units and assumptions
Uses international metric and imperial definitions. One inch is exactly 0.0254 metres; one foot is 12 inches. These are lengths, rather than areas or volumes.
Calculator results use floating-point arithmetic and are rounded for display. The reference table below uses up to 12 significant digits.
Kilometres to Millimetres table
| Kilometres (km) | Millimetres (mm) |
|---|---|
| 0 | 0 |
| 1 | 1,000,000 |
| 5 | 5,000,000 |
| 10 | 10,000,000 |
| 25 | 25,000,000 |
| 100 | 100,000,000 |
| 1,000 | 1,000,000,000 |
About this conversion
What is the formula for kilometres to millimetres?
mm = km × 1,000,000. Multiply the amount in kilometres by 1,000,000 to get millimetres. The displayed factor and results are rounded to 12 significant digits.
How do I convert back to kilometres?
Use the millimetres to kilometres calculator to reverse this conversion. You can also use Swap units in the calculator above.
Can I use a different pair of units?
Choose another unit in the calculator, or open the length converter to browse all supported pairs.