Convert Millimeters to Kilometers
1 millimeter (mm) equals 0.000001 kilometers (km).
1 mm = 0.000001 km
Type in either box. Scientific notation works: 1.5e-3.
Converting a list? Use the bulk millimeter to kilometer converter to paste a column from Excel.
How to Convert Millimeter to Kilometer
- 1 mm = 0.000001 km
- 1 km = 1000000 mm
- Example: convert 15 mm to km: 15 mm = 15 × 0.000001 km = 0.000015 km
Formula
km = mm ÷ 1000000
Derivation from SI units:
- 1 mm = 10⁻³ m
- 1 km = 10³ m
- 1 mm = 0.001 m ÷ 1000 m per km = 0.000001 km
Both units are defined exactly, so the factor is exact. Millimeter definition: millimeter; Kilometer definition: kilometer.
Worked examples
- A reading of 8 mm converts to 0.000008 km.
8 mm × 0.000001 = 0.000008 km - A value of 30 mm is 0.00003 km.
30 mm × 0.000001 = 0.00003 km
Millimeter to Kilometer conversion table
| Millimeters (mm) | Kilometers (km) |
|---|---|
| 0.1 mm | 1 × 10⁻⁷ km |
| 0.5 mm | 5 × 10⁻⁷ km |
| 1 mm | 0.000001 km |
| 2 mm | 0.000002 km |
| 3 mm | 0.000003 km |
| 5 mm | 0.000005 km |
| 6 mm | 0.000006 km |
| 8 mm | 0.000008 km |
| 10 mm | 0.00001 km |
| 12 mm | 0.000012 km |
| 15 mm | 0.000015 km |
| 16 mm | 0.000016 km |
| 20 mm | 0.00002 km |
| 25 mm | 0.000025 km |
| 25.4 mm | 0.0000254 km |
| 30 mm | 0.00003 km |
| 50 mm | 0.00005 km |
| 75 mm | 0.000075 km |
| 100 mm | 0.0001 km |
| 150 mm | 0.00015 km |
| 300 mm | 0.0003 km |
| 500 mm | 0.0005 km |
| 1000 mm | 0.001 km |
Where it's used
Millimeters are used for engineering drawings and machining tolerances, while kilometers appear in road distances and speed (km/h). Both measure length and distance, so the conversion is a fixed factor.
Millimeter to other length units
| Conversion | 1 mm equals |
|---|---|
| millimeter to meter | 0.001 m |
| millimeter to kilometer | 0.000001 km |
| millimeter to centimeter | 0.1 cm |
| millimeter to micrometer | 1000 µm |
| millimeter to nanometer | 1000000 nm |
| millimeter to angstrom | 10000000 Å |
| millimeter to mile | 6.213711922 × 10⁻⁷ mi |
| millimeter to yard | 0.001093613298 yd |
| millimeter to foot | 0.003280839895 ft |
| millimeter to inch | 0.03937007874 in |
| millimeter to mil | 39.37007874 mil |
| millimeter to nautical mile | 5.399568035 × 10⁻⁷ nmi |
Frequently asked questions
How many kilometers are in 1 millimeter?
1 mm = 0.000001 km.
How do I convert millimeters to kilometers?
Multiply the value in mm by 0.000001, or divide it by 1000000. For example, 15 mm × 0.000001 = 0.000015 km.
Is the mm to km conversion exact?
Yes. Both units are defined exactly, and 1 mm is exactly 0.000001 km.
Sources
- The International System of Units (SI), 9th edition (SI Brochure), Bureau International des Poids et Mesures , Table 7, SI prefixes.
Last reviewed: . Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.
Cite this page
APA
Scientific Converters. (2026, October 15). Convert Millimeters to Kilometers. Retrieved October 17, 2026, from https://scientificconverters.com/length/millimeters-to-kilometers/
IEEE
Scientific Converters, "Convert Millimeters to Kilometers," scientificconverters.com. Accessed: Oct. 17, 2026. [Online]. Available: https://scientificconverters.com/length/millimeters-to-kilometers/