Convert Kilometers to Millimeters
km to mm · length conversion
What are kilometers and millimeters?
A kilometer is 1,000 meters, the standard metric unit for road distances. A millimeter is one-thousandth of a meter, about the thickness of a credit card. For scale: a doorway is about 2 m (6.6 ft) tall, and a marathon is 42.2 km (26.2 mi).
How to convert kilometers to millimeters
1 km = 1,000,000 mm. To convert, multiply the number of kilometers by 1,000,000. For example, 5 km = 5,000,000 mm, and 20 km = 20,000,000 mm. To go the other way, multiply millimeters by 0.000001 (since 1 mm = 0.000001 km).
Kilometers to Millimeters conversion table
| Kilometers (km) | Millimeters (mm) |
|---|---|
| 1 | 1,000,000 |
| 2 | 2,000,000 |
| 5 | 5,000,000 |
| 10 | 10,000,000 |
| 20 | 20,000,000 |
| 50 | 50,000,000 |
| 100 | 100,000,000 |
FAQ
What is 1 km in mm?
1 km = 1,000,000 mm. To convert any amount, multiply the number of kilometers by 1,000,000.
How do I convert millimeters back to kilometers?
Go the other way: 1 mm = 0.000001 km, so multiply millimeters by 0.000001 to get kilometers.
Is a kilometer bigger than a millimeter?
Yes — 1 km is the larger unit, equal to 1,000,000 mm.
Are these length conversions exact?
They use the standard internationally-defined conversion factors. Results are rounded to six significant figures for readability, which is accurate enough for everyday and most technical use.