# Millimeters to Kilometers Conversion

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

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

## How to Convert Millimeters to Kilometers

To convert a millimeter measurement to a kilometer measurement, divide the length by the conversion ratio.

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 millimeters divided by 1,000,000.

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

## Millimeters

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 a 1/299,792,458 second time interval.

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 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.

## Kilometers

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.

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 103. Kilometers can be abbreviated as km; for example, 1 kilometer can be written as 1 km.

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 combination with 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

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

## References

1. United States Mint, Coin Specifications, https://www.usmint.gov/learn/coin-and-medal-programs/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, https://physics.nist.gov/cuu/pdf/sp811.pdf