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Using a Fuel Purchase Record to Calculate Fuel Economy

Maintaining Your Fuel Purchase Records

A fuel purchase record is useful for tracking fuel economy, fuel expenditures, and vehicle mileage over time. My MPG provides a downloadable form for tracking fuel purchases. The figure below describes the kind of data that should be entered in a fuel purchase record. Some fields are required to calculate MPG, others are used to record optional information that also may be useful.

Diagram explaining how to maintain a fuel purchase record. Required information includes the odometer reading or miles traveled between fillups and the gallons of fuel purchased. Optional information includes fill-up cost, date, driving conditions, and MPG.

Calculating MPG from Fuel Purchase Records

Calculating fuel economy from fuel purchase data is quite simple: MPG is simply calculated as the number of miles traveled per gallons of fuel used. The figures below show how fuel purchase data can be used to calculate MPG. These methods are only valid if the tank was filled completely for the current purchase and the previous purchase.

Using Odometer Reading

Calculating your MPG using the odometer reading. Step 1. Distance traveled is calculated by subtracting the new odometer reading from the previous one. Step 2. MPG is calculated by dividing the distance traveled by the gallons of fuel consumed.

Using Miles Traveled

Calculating your MPG Using Miles Traveled. Step 1. If miles traveled is already calculated by a trip odometer or some other method, MPG is calculated by simply dividing the distance traveled by the gallons of fuel consumed.