Charging
EV Charging Cost Calculator
Work out what one charging session costs from the energy you add, charging losses and your electricity price. Compare up to three tariffs.
Results are mathematical estimates from the values you enter — not measurements and not data about a specific product or vehicle.
How does the EV Charging Cost Calculator work?
Charging cost = energy added to the battery ÷ charging efficiency × price per kWh, plus any session fee. Energy added is usable capacity × (target SoC − starting SoC). The calculator does not know your vehicle: enter its usable capacity and consumption from the manufacturer or your own records.
Formula
E(battery) = C × (SoC(to) − SoC(from))
E(grid) = E(battery) ÷ η
cost = E(grid) × price + fee
range added = E(battery) ÷ consumption × 100Worked example
60 kWh from 20% to 80% → 36 kWh into the battery ÷ 0.90 = 40 kWh from the grid × $0.15 = $6.00.
Limitations and warnings
- Usable capacity is lower than the gross capacity some brochures quote; use the usable figure.
- Time-of-use tariffs, demand charges, idle fees and taxes are not modelled unless you include them in the price or fee.
Four values that are often confused
- Nominal capacity (Ah)
- Charge a battery delivers under rated conditions, usually over 20 hours (C20) at 25 °C.
- Usable capacity
- The part of the nominal capacity you can use without damaging the battery — about 50% for lead-acid, 80–90% for LiFePO4.
- Cranking current (CCA)
- Current deliverable for a short time in the cold to start an engine. It measures power, not stored charge, and cannot be converted to Ah.
- Stored energy (Wh)
- Ah × voltage. The right unit to compare batteries of different voltages.