Kilometers per hour is a unit of measurement using length in kilometers and time in hours, and thus it acts as a derived unit for both speed and velocity. The proper shorthand for this unit is km/h, however kph or kmph are sometimes used.
Traffic speed limits in Canada are posted in km/h in addition to automobile speedometers for the country using the same units. Both speed and velocity are measured by taking the distance traveled during some duration, and dividing that length by a time.
Please see below to convert among various units for speed/velocity: