The abbreviation "kph" means the number of kilometers traveled in an hour, whereas "mph" is the number of miles traveled in an hour. Convert mph to kph by taking the mph and multiply it by 1.61. The inverse formula is to take the kph and multiply the figure by 0.61. In other words, 1 mile is 1.61 kilometers, and 1 kilometer is 0.61 miles.

The figure for kph is higher than that of the equivalent mph because a kilometer is shorter than a mile. For instance, a car traveling 60 mph is going 96.5 kph. Conversely, a train traveling 120 kph goes 74.5 mph.

Both kph and mph can be broken down into feet per second and meters per second. To do this for kilometers, multiply the overall speed by 1,000, and then divide by 3,600. For example, 120 kph is 120,000 meters divided by 3,600, which equals 33.3 meters per second. For mph, multiply the speed by 5,280 before dividing by 3,600. For example, 60 mph is 316,800 feet divided by 3,600, which equals 88 feet per second.

The major difference between kph and mph is the metric system and U.S. customary units. There are 1,000 meters in a kilometer. One meter is approximately 3.3 feet, or slightly more than a yard. Therefore, 1 kilometer is 3,280 feet. One mile is 5,280 feet, or 1,609 meters.