Gas Cost Calculator

Fuel economy measures how efficiently a vehicle converts fuel into distance traveled. In the United States, it is expressed in miles per gallon (MPG) — the number of miles a vehicle can travel on one gallon of gasoline. The EPA tests new vehicles under standardized city and highway driving cycles and publishes combined MPG ratings for consumer comparison.

Real-world fuel economy often differs from EPA estimates. Factors like aggressive acceleration, highway speeds above 65 mph, air conditioning use, roof racks, tire pressure, and cold weather can all reduce your effective MPG by 10–30%. For accurate budgeting, use your actual observed MPG from recent fill-ups rather than the EPA label estimate.

Fuel economy has an outsized effect on operating costs at current gas prices. The difference between a 20 MPG and a 30 MPG vehicle at $3.50/gallon over 12,000 annual miles amounts to about $700 per year in fuel savings. Over five years, that is $3,500 — a significant factor when comparing vehicle total cost of ownership.

1. Enter the trip distance in miles (one way).
2. Enter your vehicle's fuel efficiency in MPG (check your dashboard display or recent fill-up data).
3. Enter the current gas price per gallon in your area.
4. Check the "Round Trip" box if you want to calculate both legs of the journey.
5. Review the estimated fuel cost, total distance, gallons needed, and cost per mile.
6. The quick reference table shows how costs change at different gas price levels for easy comparison.

Maintaining proper tire inflation is one of the easiest ways to preserve your vehicle's fuel economy. Tires inflated to the manufacturer-recommended PSI (found on the door jamb sticker) reduce rolling resistance. Under-inflated tires can reduce fuel economy by 0.2–0.5% for every 1 PSI below the recommended level across all four tires.

Driving at steady highway speeds between 55–65 mph maximizes fuel economy for most gasoline vehicles. For every 5 mph above 65 mph, you can expect to pay roughly 7–14% more per gallon due to increased aerodynamic drag. On long trips, cruise control helps maintain a steady speed and avoids the fuel-wasting effects of unnecessary acceleration and deceleration.

Reducing excess weight and cargo improves fuel economy. An extra 100 pounds of cargo reduces fuel efficiency by about 1%. Roof-mounted cargo boxes or open-bed loads create significant aerodynamic drag and can reduce MPG by 2–17% depending on speed and cargo size. Removing roof racks when not in use is a simple step that can improve daily fuel economy noticeably.