# Square Millimeters to Square Kilometers Conversion

Enter the area in square millimeters below to get the value converted to square kilometers.

Results in Square Kilometers: 1 sq mm = 1.0E-12 sq km
Hint: use a scientific notation calculator to convert E notation to decimal

## How to Convert Square Millimeters to Square Kilometers

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

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

square kilometers = square millimeters ÷ 1,000,000,000,000

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

For example, here's how to convert 5,000,000 square millimeters to square kilometers using the formula above.
5,000,000 sq mm = (5,000,000 ÷ 1,000,000,000,000) = 5.0E-6 sq km

Square millimeters and square kilometers are both units used to measure area. Keep reading to learn more about each unit of measure.

## Square Millimeters

One square millimeter is equal to the area of a square with edges that are 1 millimeter in length.

The square millimeter, or square millimetre, is a multiple of the square meter, which is the SI derived unit for area. In the metric system, "milli" is the prefix for 10-3. A square millimeter is sometimes also referred to as a square mm. Square millimeters can be abbreviated as sq mm, and are also sometimes abbreviated as mm². For example, 1 square millimeter can be written as 1 sq mm or 1 mm².

## Square Kilometers

One square kilometer is equal to the area of a square with sides that are 1 kilometer in length.

The square kilometer, or square kilometre, is a multiple of the square meter, which is the SI derived unit for area. In the metric system, "kilo" is the prefix for 103. A square kilometer is sometimes also referred to as a square km. Square kilometers can be abbreviated as sq km, and are also sometimes abbreviated as km². For example, 1 square kilometer can be written as 1 sq km or 1 km².

## Square Millimeter to Square Kilometer Conversion Table

Square millimeter measurements converted to square kilometers
Square Millimeters Square Kilometers
1 sq mm 0.000000000001 sq km
2 sq mm 0.000000000002 sq km
3 sq mm 0.000000000003 sq km
4 sq mm 0.000000000004 sq km
5 sq mm 0.000000000005 sq km
6 sq mm 0.000000000006 sq km
7 sq mm 0.000000000007 sq km
8 sq mm 0.000000000008 sq km
9 sq mm 0.000000000009 sq km
10 sq mm 0.00000000001 sq km
100 sq mm 0.0000000001 sq km
1,000 sq mm 0.000000001 sq km
10,000 sq mm 0.00000001 sq km
100,000 sq mm 0.0000001 sq km
1,000,000 sq mm 0.000001 sq km
10,000,000 sq mm 0.00001 sq km
100,000,000 sq mm 0.0001 sq km
1,000,000,000 sq mm 0.001 sq km
10,000,000,000 sq mm 0.01 sq km
100,000,000,000 sq mm 0.1 sq km
1,000,000,000,000 sq mm 1 sq km