A realistic trip budget includes energy, tolls, parking, and destination fees—not just distance. Calculate a base estimate, then add a clearly labeled contingency instead of hiding uncertainty inside the numbers.
Gasoline or diesel cost
Fuel cost = trip miles ÷ expected mpg × price per gallon.
For a 360-mile trip at 30 mpg and $3.40 per gallon: 360 ÷ 30 = 12 gallons; 12 × $3.40 = $40.80. Use recent real-world highway economy for the loaded vehicle, not only the window-sticker value. Add local driving at the destination and a small reserve.
EV charging cost
Charging cost = energy purchased × price per kWh, plus session, parking, idle, or tax charges where applicable. Public networks may price by energy, time, session, or membership level. Estimate energy from the vehicle planner and recent consumption, then verify each network's current price.
Do not assume the full battery capacity is purchased at every stop. Use the expected increase in state of charge and allow for charging losses.
Tolls and road charges
Check the toll operator's official calculator. Rates can depend on time, vehicle class, axle count, payment method, occupancy, or transponder. App estimates may exclude congestion-based prices or later administrative fees.
Parking and destination costs
- Garage or lot rate, including daily maximum
- Reservation or service fee
- Event, airport, or overnight surcharge
- Hotel destination or valet fee
- Transit or rideshare from a remote parking area
Confirm whether the posted price includes taxes and whether an “up to” rate requires a specific entry time or validation.
Use a one-page worksheet
| Category | Outbound | Return | Total |
|---|---|---|---|
| Fuel or charging | _____ | _____ | _____ |
| Tolls or ferry | _____ | _____ | _____ |
| Parking | _____ | _____ | _____ |
| Other transport | _____ | _____ | _____ |
| Contingency | _____ |
Compare routes on total cost
A toll-free route can cost more if it adds substantial mileage and time. A distant parking lot may save money but add transit fares. Put both route options into the same worksheet before deciding.
Related guidance
- Verify fuel prices and detour savings
- Estimate energy between charging stops
- Confirm parking rates and access
Reviewed July 19, 2026. All prices are planning estimates; verify current operator terms before purchase.