How Much Will Your Trip Cost in Gas? (Calculate)

Why Fuel Cost Calculations Matter More Than You Think

A 600-mile round trip in a 20 MPG SUV at $3.60/gallon costs $108 in fuel. The same trip in a 35 MPG sedan costs $62. Over 20 trips a year, that's a $920 annual difference — just in gas — for what might be a $3,000 price difference between vehicles. The math often makes the more fuel-efficient vehicle a clear financial winner, but only if you run the actual numbers.

Fuel cost calculations also matter for reimbursement accuracy. The IRS standard mileage rate ($0.67/mile for 2024) is designed to cover fuel, depreciation, insurance, and maintenance — not just gas. Your actual fuel cost per mile is typically $0.08–0.18 depending on your vehicle and local prices. If you're being reimbursed at the IRS rate for personal vehicle use, you're receiving considerably more than your fuel cost alone.

For commuters, the annual fuel cost is often the most underappreciated car expense. A 40-mile daily round-trip commute in a 25 MPG vehicle at $3.50/gallon costs $2,016/year. An electric vehicle with $0.12/kWh electricity costs roughly $420/year for the same commute. The difference isn't trivial over a 5-year car ownership period.

Calculate Your Trip Fuel Cost

Enter distance, your vehicle's MPG, and current gas price to get exact fuel cost and cost per mile — plus vehicle comparison and annual fuel projections.

Calculate Fuel Cost

How to Calculate and Reduce Your Fuel Costs

1
Find your vehicle's real-world MPG
The most accurate method: fill tank completely, reset trip odometer, drive normally until nearly empty, fill up again. Miles on odometer ÷ gallons added = your actual MPG. Alternatively, check your car's trip computer if it shows average MPG — that's reasonably accurate. EPA estimates from fueleconomy.gov are a starting point but often optimistic by 10–20%.
2
Get current gas prices for your route
GasBuddy.com and Google Maps show real-time gas prices by location. For long road trips, prices can vary significantly by state — gas is typically cheaper in the Southeast and more expensive in California, Hawaii, and the Pacific Northwest. If your route crosses state lines, check prices along the way and plan fill-ups accordingly.
3
Calculate cost-per-mile to compare driving vs. flying
Your fuel cost per mile is (gas price ÷ MPG). Add $0.08–0.15/mile for wear and tear (oil, tires, depreciation attribution). Compare total driving cost against all-in flight cost including baggage, airport parking or rideshare, and travel time value. For solo travel, driving often wins under 500 miles. For families of 4, driving almost always wins on cost.
4
Use the vehicle comparison to evaluate purchases
Enter your current vehicle's MPG vs. a more efficient alternative. The calculator shows annual savings at your mileage level. Divide the price premium of the efficient vehicle by annual savings to get the payback period. A hybrid that costs $3,000 more but saves $900/year in fuel pays back in 3.3 years — with additional savings from then on.

Driving vs. Flying Cost Comparison

When Driving Wins

✓Family of 4 on any trip under 1,000 miles (per-person flight costs multiply)
✓Pet owners (flight pet fees add $100–200 each way)
✓When you need a car at the destination anyway
✓Under 400 miles solo when you value flexibility
✓When there's significant luggage (checked bag fees)

When Flying Wins

✗Solo travel over 500 miles (time value of 10+ hours driving)
✗Cross-country trips where time is money
✗When advance purchase flight prices dip below $100
✗When rental car at destination adds meaningful cost to driving
✗International trips where driving isn't an option

Fuel Cost Questions

How do I calculate fuel cost for a hybrid vehicle?

Use the combined MPGe (miles per gallon equivalent) for the portion of your trip that runs on gas. For plug-in hybrids, calculate the all-electric range portion at your electricity cost ($0.12–0.20/kWh × kWh/mile) and the remaining miles at your gas MPG and gas price. Most hybrid calculators on fueleconomy.gov can help with this breakdown.

What's the IRS mileage rate and when should I use it?

The IRS standard mileage rate for 2024 is $0.67/mile for business use. This is what employers can reimburse you for business driving, tax-free. Your actual fuel cost per mile is almost always significantly less than $0.67 — the rate also covers depreciation, insurance, and maintenance. If your employer reimburses at the IRS rate, you're being compensated generously for actual fuel costs.

Does air conditioning significantly affect fuel economy?

Yes — running AC at highway speeds reduces MPG by 5–10%, and city driving with AC can drop it by 10–25%. In extreme heat, this is unavoidable. The fuel savings from turning off AC at highway speeds (below ~45 mph, open windows are more efficient; above 45 mph, AC is more efficient than open windows creating drag) are relatively minor — typically $2–5 per tank.

Calculate Your Exact Fuel Cost

Trip cost, cost per mile, annual fuel cost, and vehicle comparison — all from your actual MPG and local gas prices.

Use the Fuel Cost Calculator