When you are travelling by car, plane or train, in the U.S., your speed is measured in miles per hour. At any given point in time, you are travelling at a specific speed, such as 35 mph or 65 mph, but this does not remain constant throughout your trip. By calculating average mph, you can see how you progressed overall--taking into account the various speed limits and traffic conditions. You may also want to know your average mph to determine your automobile's fuel efficiency.
Enter the total number of miles travelled into the calculator. Use decimal numbers to represent total mileage if the mileage is not a perfect whole number. For example, 55.5 miles represents 55 plus one-half mile.
2
Press the "division" key on your calculator.
3
Enter the total number of hours travelled. Use decimal numbers to represent the hours if the time travelled was not a perfect whole number. For example, use 1.75 hours to represent one hour and 45 minutes. In order to convert minutes travelled into a decimal number, you must divide the minutes by 60, which is the total number of minutes in one hour. For instance, 48 minutes is 0.8 of one hour because 48/60 equals 0.8.
4
Press the "equal sign" key to calculate the average mph.
For example, to find the average mph for a trip where you travelled 150 miles in two hours and 48 minutes, you must enter "150 / 2.8 =" into the calculator. The completed equation will determine that the average mph for the trip was 53.57 mph.
