18 centimeters in millimeters

Conversion formula
How to convert 18 centimeters to millimeters?

We know (by definition) that: $1\mathrm{cm}=10\mathrm{mm}$

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

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

Conclusion: 18 ⁢ cm = 180 ⁢ mm

Conversion in the opposite direction

The inverse of the conversion factor is that 1 millimeter is equal to 0.00555555555555556 times 18 centimeters.

It can also be expressed as: 18 centimeters is equal to $\frac{1}{\mathrm{0.00555555555555556}}$ millimeters.

Approximation

An approximate numerical result would be: eighteen centimeters is about one hundred and eighty millimeters, or alternatively, a millimeter is about zero point zero one times eighteen centimeters.