Formula
km to mm conversion formula
Use this relationship for a direct conversion:
mm = km x 1,000,000
Worked example
2 km = 2,000,000 mm.
Metric factors and international inch, foot, yard, mile, and nautical mile definitions are exact.
Length conversion
Convert Kilometer to Millimeter
1 kilometer (km) equals 1,000,000 millimeter (mm). Enter any value below to convert from km to mm.
Enter a value and choose units. Results update instantly.
1 km = 1,000,000 mm
All Length units
From 1 km| Unit | Value |
|---|---|
| Meter m | 1,000 |
| Kilometer km | 1 |
| Centimeter cm | 100,000 |
| Millimeter mm | 1,000,000 |
| Micrometer μm | 1,000,000,000 |
| Nanometer nm | 999,999,999,999.9998779297 |
| Inch in | 39,370.0787401575 |
| Foot ft | 3,280.8398950131 |
| Yard yd | 1,093.6132983377 |
| Mile mi | 0.6213711922 |
| Nautical mile nmi | 0.5399568035 |
| Light-year ly | 1.057000834e-13 |
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Quick reference
Kilometer to Millimeter table
| Kilometer (km) | Millimeter (mm) |
|---|---|
| 0.01 | 10,000 |
| 0.1 | 100,000 |
| 1 | 1,000,000 |
| 2 | 2,000,000 |
| 5 | 5,000,000 |
| 10 | 10,000,000 |
| 25 | 25,000,000 |
| 50 | 50,000,000 |
| 100 | 100,000,000 |
| 1,000 | 1,000,000,000 |
From unit
About the kilometer
One thousand meters.
Symbol: km
To unit
About the millimeter
One thousandth of a meter.
Symbol: mm
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Source
Conversion standard
Definitions are checked against NIST SP 811: Guide for the Use of the SI. Calculations use full internal precision before display rounding.
View the complete length converterQuestions
km to mm FAQ
How do you convert kilometer to millimeter?
Use the formula mm = km x 1,000,000. 1 kilometer (km) equals 1,000,000 millimeter (mm).
Is the km to mm conversion exact?
Both unit definitions use exact factors. Only the displayed decimal may be rounded.