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Fuel Cost Calculator

Calculate fuel cost for any trip and compare two vehicles to see annual savings.

Quick Answer

Trip fuel cost = (Distance ÷ MPG) × Price per gallon. A 500-mile trip at 28 MPG with $3.50/gal fuel costs about $62.50. Driving 12,000 miles per year at that rate costs about $1,500 annually.

Trip Details

Results

$62.50

Trip Cost

17.9

Gallons Used

$1500

Annual Cost (12K mi)

429

Annual Gallons

Vehicle Comparison (35 MPG vs 28 MPG)

$50.00

Trip Cost

$1200

Annual Cost

$300/yr

Annual Savings

About This Tool

The Fuel Cost Calculator helps you estimate the cost of fuel for any trip based on distance, your vehicle’s fuel economy, and current fuel prices. It also projects annual fuel costs based on 12,000 miles of driving per year, which is the national average. The comparison feature lets you see exactly how much you would save by switching to a more fuel-efficient vehicle.

Understanding MPG Ratings

The EPA fuel economy ratings on new vehicle window stickers represent a combined city and highway estimate tested under controlled conditions. Real-world MPG varies based on driving style, terrain, weather, tire pressure, and vehicle maintenance. Most drivers get 10-15% lower fuel economy than the EPA rating. Highway driving typically yields 20-30% better MPG than city driving due to fewer stops and more efficient cruising speeds.

The Gallons Per Mile Perspective

Thinking in gallons per mile rather than miles per gallon reveals the true savings of efficiency improvements. Upgrading from 15 MPG to 20 MPG saves 1.67 gallons per 100 miles. Upgrading from 30 MPG to 35 MPG saves only 0.48 gallons per 100 miles. The biggest savings come from improving the least efficient vehicles, not from squeezing extra MPG from already-efficient ones. This is known as the MPG illusion.

Regional Fuel Price Variation

Fuel prices vary significantly by region. California, Hawaii, and the Pacific Northwest consistently have the highest gas prices in the US, often $1-2 per gallon above the national average. Gulf Coast states and the Midwest typically have the lowest prices. Planning a road trip through lower-cost states or filling up before entering expensive areas can save meaningful money on long trips.

Frequently Asked Questions

Should I use city or highway MPG?
Use city MPG for urban driving, highway MPG for road trips, or the combined rating for mixed use. If your trip is mostly interstate, use highway MPG. For daily commutes with stop-and-go traffic, city MPG is more accurate.
How much does driving speed affect fuel cost?
Every 5 mph over 50 mph costs roughly an additional $0.20-$0.30 per gallon in fuel economy loss. Driving 75 mph instead of 65 mph can reduce your MPG by 15-20%. The aerodynamic drag increases exponentially with speed, making this one of the biggest controllable factors in fuel economy.
Is it cheaper to drive or fly for long trips?
For solo travelers, flying is often cheaper for trips over 500 miles when you factor in fuel, meals, lodging, and wear on your vehicle. For families of 3-4, driving is usually cheaper up to about 1,000 miles since you only pay for one vehicle regardless of passengers.
How accurate are the annual cost estimates?
They are based on 12,000 miles per year at a constant fuel price. Your actual costs will vary with changing gas prices, seasonal driving patterns, and maintenance-related MPG changes. The estimate gives a good baseline for comparison purposes.
Does AC affect fuel cost significantly?
Running AC can reduce fuel economy by 10-25% in city driving. On the highway, the difference is smaller (5-10%) because the engine is already working hard. At highway speeds, AC is more efficient than rolling windows down, which creates aerodynamic drag.