How it works
How to calculate it
The calculator applies the values you enter to this formula:
Trip fuel cost = round-trip miles ÷ MPG × average fuel price.
How to use this calculator
- Add outbound, return, and destination miles.
- Use route-appropriate MPG.
- Apply an average fuel price across the trip.
Worked example
An 850-mile trip at 30 MPG and $3.50/gal uses about 28.3 gallons and costs about $99.
Important assumptions
- Enter round-trip distance.
- Fuel price and MPG are averaged across the route.
- Food, lodging, tolls, parking, and maintenance are excluded.
Common mistakes to avoid
- Entering one-way miles.
- Using the cheapest local fuel price for the whole route.
- Calling fuel cost the total trip budget.
Method reviewed June 10, 2026. Prices and rates are user-provided defaults and should be replaced with local values.