How to Calculate the Average Speed of a Car

You know your speedometer shows you how fast you're going, and you're odometer tells you how far you've traveled. What you may not know is that you can also use the odometer to tell you the average speed of your car. By using some simple math calculations that you learned before high school, you can figure out the average speed of a car, which comes in quite handy when you're planning a long trip or calculating your gas mileage.

Instructions

1. Write down your odometer reading and the time of day before you depart on your trip; do the same when you reach your destination.

2. Subtract the beginning odometer reading from the ending odometer reading; this is the total amount of miles traveled.

3. Determine the total time of the trip by subtracting the beginning time from the ending time and round it off to the nearest 15 minutes. For example, if you drove for 3 hours and 40 minutes, round your time off to 3 hours and 45 minutes, which equals three quarters of an hour (see conversions in Tip section).

4. Divide the total miles driven by the total time. This will give you the average speed of your car during the trip.

Tips & Warnings

• 1 hour and 15 minutes equals 1.25 hours 1 hour and 30 minutes equals 1.50 hours 1 hour and 45 minutes equals 1.75 hours