Fuel Cost Per Mile Calculator
This fuel cost per mile calculator divides the current gas price by your vehicle's fuel economy in miles per gallon (MPG) to find the exact fuel cost for every mile you drive. It also calculates annual fuel spending and shows how much you would save by switching to a more fuel-efficient vehicle. The formula is simple: cost per mile = price per gallon / MPG. Enter your current gas price per gallon (check GasBuddy or AAA for local prices), your fuel economy, and your annual mileage to get a complete picture of your fuel costs.
Fuel cost formula
Cost per mile = Gas Price ($/gal) / Fuel Economy (MPG) Annual Fuel Cost = Cost per mile * Annual Miles
This is the formula used by the EPA and DOE on the official fueleconomy.gov website to calculate annual fuel cost. The EPA assumes 15,000 miles per year and 55% city/45% highway driving for their estimates.
Tips for reducing fuel cost per mile
- Maintain proper tire inflation: underinflated tires increase rolling resistance and reduce MPG by 0.2% per psi below recommended. Check monthly.
- Use the recommended fuel octane: using premium in an engine that only requires regular does not improve fuel economy and wastes money.
- Reduce highway speed: driving 60 mph instead of 70 mph improves fuel economy by 10-15% for most vehicles.
- Remove excess weight: every 100 lb of extra cargo reduces MPG by about 1-2% for a typical vehicle.
- Use cruise control on highways: maintains a steady speed and reduces the fuel-wasting speed fluctuations of manual throttle control.
Frequently asked questions
How do you calculate fuel cost per mile?
Fuel cost per mile = fuel price per gallon / fuel economy (MPG). For example, at $3.50 per gallon and 30 MPG: $3.50 / 30 = $0.117 per mile. Multiply by annual miles driven to find annual fuel cost.
How much does MPG matter?
Going from 20 MPG to 25 MPG at $3.50/gallon saves $0.070/mile, or $875/year at 12,500 miles annually. Going from 30 to 35 MPG saves $0.033/mile, or $413/year. The savings are larger at lower MPG levels because of diminishing returns at higher efficiency.
What is the average American's annual fuel cost?
The U.S. Department of Energy estimates the average American drives approximately 13,500 miles per year. At a national average gas price around $3.50 and average vehicle fuel economy around 28 MPG combined, annual fuel cost is approximately $1,688.
How do I find my actual MPG?
Fill your tank completely, reset the trip odometer, drive normally, then fill up completely again. Divide miles driven by gallons pumped. Repeat over several tanks for an accurate average. Most modern cars also display this in the instrument cluster.
How does driving style affect fuel economy?
Aggressive acceleration and hard braking reduce fuel economy by 15-30% in city driving. Highway fuel economy is most affected by speed: EPA tests show fuel economy drops roughly 14% when driving at 70 mph vs 55 mph, due to aerodynamic drag scaling with speed squared.
Official sources
- US DOE Fuel Economy: fueleconomy.gov - official EPA fuel economy ratings and cost calculations.
- EPA: epa.gov/greenvehicles - green vehicle and fuel economy data.
Reviewed by the CalculatorHub team, edited by James Graham, 15 June 2026. See our methodology.