There's no single number that directly converts km/h to mph. You need a conversion factor. Here's how it works:

* 1 kilometer (km) is approximately equal to 0.621371 miles.

* 1 hour is equal to 1 hour.

To convert km/h to mph, you multiply the speed in km/h by 0.621371.

Example:

* 100 km/h * 0.621371 = 62.1371 mph (approximately)

So, 100 km/h is about equal to 62.14 mph.