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Fuel Cost Calculator

Knowing your real fuel cost per mile is the difference between budgeting by guess and budgeting by number. This calculator turns gas price, MPG, and annual mileage into cost per mile, monthly spend, and annual totals — plus a commute-specific breakdown and an honest EV charging comparison so you can see whether an electric car would actually save you money.

Your Vehicle & Driving

The Fuel Cost Formula

Every fuel-cost figure on this page comes from one relationship:

Cost per mile = gas price ÷ MPG   |   Annual cost = cost per mile × miles

At $3.50/gallon and 28 MPG, each mile costs 12.5¢. Over 12,000 miles that is $1,500 a year. The EV comparison uses the same shape: electricity rate ÷ mi/kWh gives the per-mile cost (e.g. $0.16 ÷ 3.5 = 4.6¢), then multiplies by miles for the annual figure. These simple products are why small MPG gains and shorter commutes move the annual number so much.

Cost per Mile by Vehicle Class

The table below assumes $3.50/gallon, 12,000 miles/year, and typical EPA-combined economy for each class. Your own numbers will differ — that is exactly what the calculator is for.

VehicleFuel EconomyCost / MileAnnual CostBest

Annual cost = 12,000 miles × (price ÷ economy). EV figures use 3.5 mi/kWh at $0.16/kWh. Electricity prices and EV efficiency vary widely by region and model.

How to Use This Calculator (3 Steps)

1
Use your real MPG
Divide the miles on your odometer between fill-ups by the gallons pumped, over three or four tanks, for a true average. Sticker MPG is optimistic — real-world is usually 15-25% lower for mixed driving.
2
Enter your commute honestly
The commute section isolates the single largest chunk of most people's driving. A 20-mile one-way commute, 5 days a week, 48 weeks a year, is 9,600 miles — often 70%+ of total annual miles.
3
Use the EV row as a reality check
The EV comparison only covers fuel. Purchase price, insurance, and maintenance swing the total ownership picture — for the full comparison use our EV vs Gas TCO calculator linked below.

Case Study

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Case Study #1

Daily Commuter Cuts Fuel Spend 62%

Maya drives 40 miles round-trip to work, 5 days a week, 48 weeks a year, in a 2018 SUV that returns 22 MPG. Gas in her region runs $3.85/gal.

Commute Cost / yr
$1,681
Total Fuel / yr
$2,100
Cost per Mile
$0.175
After Trades: Total / yr
$798

Frequently Asked Questions

How do I calculate fuel cost per mile?

Divide the gas price per gallon by your MPG. $3.50 ÷ 28 = $0.125 per mile.

How much does the average American spend on gas per year?

Roughly 13,500 miles at ~25 MPG and $3.50/gal is about $1,900 per year. A 35 MPG car cuts that to about $1,350.

Is city or highway MPG more realistic?

Real-world economy falls between the two; combined is the best single estimate. Stop-and-go commute = closer to city.

How much does a 5 MPG improvement save per year?

About $280/year for 12,000 miles at $3.50/gal (25→30 MPG). More for higher mileage or prices.

Is it cheaper to drive an EV than a gas car?

Per mile, yes on fuel alone: ~4.6¢ vs ~12.5¢. The full ownership answer depends on purchase price, insurance, and maintenance — see the TCO calculator.

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BuildFormulas Automotive Team
Transportation Cost Analytics

The BuildFormulas Automotive Team builds fuel, EV, and total-cost-of-ownership tools grounded in EPA fuel economy data and typical US utility rates.

Reviewed by BuildFormulas Editorial Review Board, Editorial Review
Last updated: August 2026