How Do I Convert Miles Per Hour to Miles Per Gallon?

Use your car's odometer to determine your distance.

Get a better picture of your fuel efficiency by determining the miles you get out of each gallon of gas. You will need to use both your speed in miles per hour and the amount of gas you put into your car for determining your efficiency. As driving and road conditions and car makes and models differ, your calculations will not be the same as those for another car or driver. Always obey all speed limits and driving laws when gathering your information.

Things You'll Need

• Paper and pencil (optional)

Instructions

1. Fill up your gas tank to full.

2. Reset your trip odometer to 0 miles. If your car doesn't have a trip odometer, note the total mileage and write it on a piece of paper.

3. Drive for one hour.

4. Calculate your miles per hour by looking at your trip odometer to determine your distance. Divide the distance your traveled by the time of one hour to determine your average speed. For example, if you went 30 miles in one hour, 30 miles / one hour = 30 miles per hour. (If your car doesn't have a trip odometer, subtract the total miles shown on the odometer prior to the trip to the figure now shown to arrive at total miles traveled.)

5. Top off your gas tank and look at the amount of gas required to refill it. This equals the amount of gas you used on your drive.

6. Divide the number of gallons used by the time to find the number of gallons per hour used by the vehicle. For example, 2 gallons / one hour = 2 gallons per hour.

7. Find the miles per gallon by dividing the speed by the number of gallons per hour. For example, 30 miles per hour / 2 gallons per hour = 15 miles per gallon.

Tips & Warnings

• If your trip takes more than one hour, simply divide the number of miles traveled by the total time to arrive at miles per hour.

References

• NASA Virtual Skies: Navigation Calculations