Conversion formula

The conversion factor from millimeters to kilometers is 1.0E-6, which means that 1 millimeter is equal to 1.0E-6 kilometers:

1 mm = 1.0E-6 km

To convert 420 millimeters into kilometers we have to multiply 420 by the conversion factor in order to get the length amount from millimeters to kilometers. We can also form a simple proportion to calculate the result:

1 mm → 1.0E-6 km

420 mm → L_(km)

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

L_(km) = 420 mm × 1.0E-6 km

L_(km) = 0.00042 km

The final result is:

420 mm → 0.00042 km

We conclude that 420 millimeters is equivalent to 0.00042 kilometers:

420 millimeters = 0.00042 kilometers

Alternative conversion

We can also convert by utilizing the inverse value of the conversion factor. In this case 1 kilometer is equal to 2380.9523809524 × 420 millimeters.

Another way is saying that 420 millimeters is equal to 1 ÷ 2380.9523809524 kilometers.

Approximate result

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

420 mm ≅ 0 km

An alternative is also that one kilometer is approximately two thousand three hundred eighty point nine five two times four hundred twenty millimeters.

Conversion table

millimeters to kilometers chart

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