## Conversion formula

The conversion factor from kilometers to millimeters is 1000000, which means that 1 kilometer is equal to 1000000 millimeters:

1 km = 1000000 mm

To convert 20 kilometers into millimeters we have to multiply 20 by the conversion factor in order to get the length amount from kilometers to millimeters. We can also form a simple proportion to calculate the result:

1 km → 1000000 mm

20 km → L(mm)

Solve the above proportion to obtain the length L in millimeters:

L(mm) = 20 km × 1000000 mm

L(mm) = 20000000 mm

The final result is:

20 km → 20000000 mm

We conclude that 20 kilometers is equivalent to 20000000 millimeters:

20 kilometers = 20000000 millimeters

## Alternative conversion

We can also convert by utilizing the inverse value of the conversion factor. In this case 1 millimeter is equal to 5.0E-8 × 20 kilometers.

Another way is saying that 20 kilometers is equal to 1 ÷ 5.0E-8 millimeters.

## Approximate result

For practical purposes we can round our final result to an approximate numerical value. We can say that twenty kilometers is approximately twenty million millimeters:

20 km ≅ 20000000 mm

An alternative is also that one millimeter is approximately zero times twenty kilometers.

## Conversion table

### kilometers to millimeters chart

For quick reference purposes, below is the conversion table you can use to convert from kilometers to millimeters

kilometers (km) millimeters (mm)
21 kilometers 21000000 millimeters
22 kilometers 22000000 millimeters
23 kilometers 23000000 millimeters
24 kilometers 24000000 millimeters
25 kilometers 25000000 millimeters
26 kilometers 26000000 millimeters
27 kilometers 27000000 millimeters
28 kilometers 28000000 millimeters
29 kilometers 29000000 millimeters
30 kilometers 30000000 millimeters