Millimeters to Kilometers Converter

Enter the length in millimeters below to get the value converted to kilometers.

Results in Kilometers:
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1 mm = 1.0E-6 km
Hint: use a scientific notation calculator to convert E notation to decimal

Do you want to convert kilometers to millimeters?

How to Convert Millimeters to Kilometers

To convert a measurement in millimeters to a measurement in kilometers, divide the length by the following conversion ratio: 1,000,000 millimeters/kilometer.

Since one kilometer is equal to 1,000,000 millimeters, you can use this simple formula to convert:

kilometers = millimeters ÷ 1,000,000

The length in kilometers is equal to the length in millimeters divided by 1,000,000.

For example, here's how to convert 5,000,000 millimeters to kilometers using the formula above.
kilometers = (5,000,000 mm ÷ 1,000,000) = 5 km

Our inch fraction calculator can add millimeters and kilometers together, and it also automatically converts the results to US customary, imperial, and SI metric values.

Millimeters and kilometers are both units used to measure length. Keep reading to learn more about each unit of measure.

What is a Millimeter?

One millimeter is equal to one-thousandth (1/1,000) of a meter, which is defined as the distance light travels in a vacuum in 1/299,792,458 of a second. One millimeter is equal to 0.0393701 inches.

The millimeter, or millimetre, is a multiple of the meter, which is the SI base unit for length. In the metric system, "milli" is the prefix for thousandths, or 10-3. Millimeters can be abbreviated as mm; for example, 1 millimeter can be written as 1 mm.

Millimeters are often represented by the smallest ticks on most metric rulers. To get a reference point of the size, the thickness of a US dime is 1.35mm.[1]

Learn more about millimeters.

What is a Kilometer?

One kilometer is equal to 1,000 meters, which are defined as the distance light travels in a vacuum in a 1/299,792,458 second time interval.[2] One kilometer is equal to 0.621371 miles.

The kilometer, or kilometre, is a multiple of the meter, which is the SI base unit for length. In the metric system, "kilo" is the prefix for thousands, or 103. Kilometers can be abbreviated as km; for example, 1 kilometer can be written as 1 km.

Learn more about kilometers.

We recommend using a ruler or tape measure for measuring length, which can be found at a local retailer or home center. Rulers are available in imperial, metric, or a combination of both values, so make sure you get the correct type for your needs.

Need a ruler? Try our free downloadable and printable rulers, which include both imperial and metric measurements.

Millimeter to Kilometer Conversion Table

Table showing various millimeter measurements converted to kilometers.
Millimeters Kilometers
1 mm 0.000001 km
2 mm 0.000002 km
3 mm 0.000003 km
4 mm 0.000004 km
5 mm 0.000005 km
6 mm 0.000006 km
7 mm 0.000007 km
8 mm 0.000008 km
9 mm 0.000009 km
10 mm 0.00001 km
100 mm 0.0001 km
1,000 mm 0.001 km
10,000 mm 0.01 km
100,000 mm 0.1 km
1,000,000 mm 1 km


  1. United States Mint, Coin Specifications,
  2. Ambler Thompson and Barry N. Taylor, Guide for the Use of the International System of Units (SI), National Institute of Standards and Technology,

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