# Millimeters to Kilometers Converter

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

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.

## 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.

## What is a Kilometer?

One kilometer is equal to 1,000 meters, which are defined as the distance light travels in a vacuum in 1/299,792,458 of a second. 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.

## 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

## 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