Kilometers are used as a unit of distance in the majority of countries worldwide, including Europe but excluding the United States. The conversion of the distance to the time in hours is the very common task, since it allows you to estimate travel time. You need to know the average speed of your car for the trip to make that conversion.
Multiply the distance, if given in miles, by the factor 1.609 to convert to kilometers. For example, 86 miles converts to 86 x 1.609 or 138.374 kilometers.
Convert the speed from miles per hour to kilometers per hour. If the speed is given in miles per hour, then multiply by 1.609. If the speed is measured in meters per second (m/s), multiply by 3.6. For example, the speed of 15 m/s corresponds to 15 x 3.6 or 54 km/h.
Divide distance (in km) by the speed (in km/h) to calculate the time (in hours). In our example, time is 138.374 km/ 54 km/h = 2.562 hours.
Multiply the decimal portion of the number of hours by the value 60 to convert to minutes. In our example, the decimal part 0.562; 0.562 x 60 = 33.72 min. After rounding to 34 minutes, 2.562 h can be expressed as 2 hours and 34 minutes.