Automotive Calculator

Fuel Cost Calculator

Estimate gallons, fuel cost, trip fees, and cost per mile from distance, fuel economy, price, and number of trips.

Estimate trip fuel cost

Distance per trip (miles)Fuel economy (MPG)Fuel price per gallon ($)Number of tripsTolls and fees per trip ($)

Calculate trip cost

Total distance300 miles

Fuel needed10 gallons

Fuel cost$35.00

Total trip cost$35.00

Cost per mile$0.117

This is a planning estimate. Traffic, speed, weather, cargo, idling, detours, and actual pump prices can change fuel use and cost.

How to use the fuel cost calculator

Enter the driving distance for one trip, your vehicle's expected miles per gallon, the local fuel price, and the number of identical trips. Add tolls or parking fees when you want a broader out-of-pocket trip estimate. For a round trip, either enter the full round-trip distance or set the number of trips to two.

Fuel cost formulas

Gallons used = total miles / miles per gallon; fuel cost = gallons used x price per gallon

Total trip cost adds tolls and fees for every trip. Cost per mile divides that total by all miles driven. The calculator does not include depreciation, maintenance, insurance, financing, or registration.

Worked example

A 300-mile trip in a vehicle averaging 30 MPG uses 10 gallons. At $3.50 per gallon, estimated fuel cost is $35.00. With no additional fees, that is about 11.7 cents per mile.

Accuracy and assumptions

• MPG is treated as an average across the entire route.
• Fuel price stays constant for the estimate.
• Distance and fees are multiplied by the number of trips.
• Electricity, hybrid charging, vehicle wear, and time are not included.
• Actual fuel economy can differ from the dashboard or official rating.

Frequently asked questions

How do I calculate a round trip?

Enter the combined distance for both directions, or enter one-way distance and set trips to two. Do not do both or the distance will be doubled twice.

Should I use city or highway MPG?

Use the rating that best matches the route, or a recent real-world average from your vehicle. Mixed driving usually falls between city and highway ratings.

Does this include vehicle ownership costs?

No. It estimates fuel plus optional trip fees only. Ownership and wear costs require additional assumptions.

Related calculators

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• Conversion Calculators

Sources and review

The calculation uses the standard miles-per-gallon relationship: distance divided by fuel economy equals gallons used. Calculator logic and examples were reviewed by the DIY Cost Tools editorial team on September 28, 2026.

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