Calculate the amount of time it took to cover the distance using a stopwatch.
Convert the time to hours. If you have a time in minutes, divide the number of minutes by 60. If you have a time in seconds, divide by 3,600 to convert to hours.
Measure the distance in kilometers with a click wheel or other measuring device. If you cannot measure in kilometers, convert to kilometers with conversion factors. For example, if you need to convert from meters to kilometers, divide the number of meters by 1,000. If you have a distance in miles, multiply the number of miles by 1.609 to convert to kilometers.
Divide the distance in kilometers by the time in hours to calculate the average speed in kilometers per hour. For example, if you travel 120 kilometers in 2 hours, divide 120 by 2 to get 60 km/h.