How do you convert m to mm

There are 1000 millimeters in 1 meter.

$$1 \text{ m} = 1000 \text{ mm}$$

For example, to convert 5 meters to millimeters:

$$5 \text{ m} \times 1000 \frac{\text{mm}}{\text{m}} = 5000 \text{ mm}$$

So, 5 meters is equal to 5000 millimeters.