Miles per hour (mph) is the standard speed unit in the United States, United Kingdom, and a few other countries, used for speed limits, vehicle speedometers, and weather forecasts. American road signs exclusively display speed limits in mph, and car enthusiasts commonly reference 0-60 mph times as a performance benchmark. One mile per hour equals exactly 1.60934 kilometers per hour.

Feet per second (ft/s) is an imperial speed unit commonly used in ballistics, fluid dynamics, and engineering calculations within the United States. Projectile velocities, pipe flow rates, and conveyor belt speeds are often expressed in ft/s in American technical documentation. One foot per second equals exactly 0.3048 meters per second or about 0.6818 miles per hour.