Gas Mileage Tips: How to Calculate and Improve Your MPG

How to Calculate MPG

Calculating gas mileage is simple: fill your tank completely, reset the trip odometer, drive normally until you need fuel again, fill up completely, and divide the miles driven by gallons used.

MPG = Miles Driven ÷ Gallons Used

For the most accurate result, track over several fill-ups and average the results. One tank can vary significantly based on driving conditions.

Why Your MPG May Be Lower Than EPA Estimates

EPA fuel economy numbers are tested under controlled laboratory conditions that don't fully represent real-world driving. Common reasons for lower real-world MPG include city driving with frequent stops, aggressive acceleration, cold weather, underinflated tires, and excess vehicle weight.

10 Proven Tips to Improve Gas Mileage

Maintain tire pressure. Underinflated tires increase rolling resistance. Check monthly and inflate to the spec on your door jamb.
Drive smoothly. Avoid rapid acceleration and hard braking. Gentle driving can improve MPG by 15–30%.
Use cruise control. On highways, maintaining constant speed is more efficient than human throttle variations.
Reduce speed. Fuel economy drops significantly above 50 mph. Each 5 mph over 50 is like paying an extra $0.20 per gallon.
Reduce idling. Idling gets 0 MPG. Turn off your engine if you'll be stopped for more than 60 seconds.
Keep up with maintenance. Clean air filters, fresh spark plugs, and proper oil all help engine efficiency.
Remove excess weight. Every 100 lbs reduces MPG by about 1%. Clean out your trunk.
Remove roof racks when not in use. They create significant aerodynamic drag, especially at highway speeds.
Plan your route. Combine errands into one trip. A warm engine is more fuel-efficient than multiple cold starts.
Use the recommended fuel grade. If your car specifies regular (87 octane), premium won't improve MPG or performance.

Track your progress with our Gas Mileage Calculator to see how these changes impact your fuel economy over time.