18 millimeters in kilometers

Conversion formula
How to convert 18 millimeters to kilometers?

We know (by definition) that: $1\mathrm{mm}=1e-06\mathrm{km}$

We can set up a proportion to solve for the number of kilometers.

Now, we cross multiply to solve for our unknown $x$:

Conclusion: 18 ⁢ mm = 1.8e-05 ⁢ km

Conversion in the opposite direction

The inverse of the conversion factor is that 1 kilometer is equal to 55555.5555555555 times 18 millimeters.

It can also be expressed as: 18 millimeters is equal to $\frac{1}{\mathrm{55555.5555555555}}$ kilometers.

Approximation

An approximate numerical result would be: eighteen millimeters is about zero kilometers, or alternatively, a kilometer is about fifty-five thousand, five hundred and fifty-five point five five times eighteen millimeters.