Millimeters to Kilometers Converter

To convert millimeters to kilometers, multiply the length by the following conversion ratio: 0.000001 kilometers/millimeter.

Since one millimeter is equal to 0.000001 kilometers, you can use this simple formula to convert:

The length in kilometers is equal to the length in millimeters multiplied by 0.000001.

For example, here's how to convert 5 millimeters to kilometers using the formula above.

Calculators give you a decimal number (such as 0.19685 in), but tape measures and woodworking rulers are marked in binary fractions of an inch—most commonly 1/16″ on carpenter tapes, 1/32″ on fine woodworking rules, and 1/64″ on machinist scales.

Here is the step-by-step worked example for converting 5 millimeters (mm) into fractional inches:

1. Find the decimal inches result: Convert 5 mm to inches to get 0.19685 in.
2. Separate the whole inches from the decimal part: Keep the whole number 0 aside, leaving the decimal remainder 0.19685.
3. Multiply the decimal part by your desired fraction denominator (16, 32, or 64) and round half up: Multiply 0.19685 by 16, 32, or 64, then round to the nearest whole number (values ending in .5 round up).
4. Reduce the fraction to lowest terms: If the rounded top number (numerator) is even, divide both top and bottom by 2 (or their Greatest Common Divisor) until the top number is odd, then combine with your whole inches.