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How many stops will the EV trip need?
A back-of-envelope planner: energy for the trip, how much the starting charge covers, and how many fast-charging stops fill the gap.
Inputs
Starting values are illustrative, not current prices or specifications. Replace each with your own.
Result
Answer
Trip energy is distance times consumption. Subtract the usable energy you start with (battery times charge above your arrival minimum) and divide the shortfall by the energy each stop adds. A 600 km trip at 20 kWh/100 km needs 120 kWh; starting at 90% on a 75 kWh battery covers 60 kWh, so two stops.
Worked example
A 600 km trip at 20 kWh/100 km needs 600 × 20 ÷ 100 = 120 kWh. A 75 kWh battery departing at 90% with a 10% minimum has 75 × 0.80 = 60 kWh usable. The shortfall is 60 kWh. Each stop charging from 10% to 80% adds 75 × 0.70 = 52.5 kWh, so 60 ÷ 52.5 rounds up to 2 stops. Charging 60 kWh at 100 kW takes 36 minutes and costs 60 × $0.55 = $33.00.
Formulas and notes
- Trip kWh = distance × energy use ÷ 100 × (1 + extra %).
- Usable at start = battery kWh × (start % − minimum %) ÷ 100; per stop = battery kWh × (charge-to % − minimum %) ÷ 100.
- Stops = round up (shortfall ÷ per-stop energy). Charging energy is the shortfall; time = energy ÷ average kW; cost = energy × price.
- It does not know where chargers are. Stops are spread by your route, charger availability and queues, and the first leg is shorter than later ones.
Planning estimate only, not professional advice. Sources, checked 2026-10-08: U.S. DOE Alternative Fuels Data Center, Electric Vehicle Charging Stations
FAQ
How many charging stops does my EV trip need?
Divide the trip energy shortfall by the energy each stop adds. The calculator does this using your battery, consumption, departure charge and the level you charge to.
What consumption should I use for a highway trip?
Use a highway figure from your own driving or trip computer. Highway speeds and cold weather raise consumption, which is what the extra-use field is for.
Why charge only to 80 percent on a road trip?
Change the charge-to level and average power to compare strategies. AFDC notes charging time varies with the state of charge and the charger power.
Does this include time spent at the charger?
Yes, as energy added divided by the average power you enter, in total across the trip. It excludes walking, queueing and detours.
How does cold weather change the plan?
It lowers range. Add an extra-use percentage here, or see the winter range loss calculator for published test results.