This calculator estimates one EV charging session from the starting charge to the target: battery energy added, electricity drawn from the grid, charging time, session cost and approximate driving range added.
Start with usable battery capacity and state of charge
A charge from 20% to 80% replaces 60% of usable battery capacity. For a 75 kWh usable battery, that means about 45 kWh stored in the pack. Electricity drawn from the outlet or charging station is higher because the charger, cables, vehicle electronics and thermal-management system use some energy.
Do not confuse gross and usable battery capacity. Manufacturers may reserve a hidden buffer, so the full nameplate figure is not always available to the driver.
Charger power and vehicle acceptance are separate limits
Common power examples across the US, Canada, UK and Australia
| Charging situation | Planning power | Important check |
|---|---|---|
| US Level 1 or portable charging | about 1.4–1.9 kW | Dedicated circuit, continuous-load rating and the supplied EVSE |
| North American Level 2 home charging | about 3.8–19.2 kW | Circuit capacity and the vehicle's onboard AC charger limit |
| UK or Australian single-phase home chargepoint | commonly about 2.3–7.4 kW | Supply capacity, dedicated circuit and vehicle AC limit |
| Three-phase AC charging | commonly 11 or 22 kW | Whether the vehicle accepts three-phase AC at that rate |
| DC fast or high-power charging | about 50–350 kW | Vehicle limit, battery temperature and the charging curve |
If a station is rated at 150 kW but the vehicle can accept only 100 kW, the calculator uses 100 kW. In real charging, even that value may be available only during part of the session.
Why DC fast charging does not hold peak power to 100%
DC charging power changes with state of charge, battery temperature, preconditioning, cell condition and station capability. Automatic mode uses a generic profile with the strongest average power through the middle of the battery window and progressively lower power above 80%.
For a particular model, a custom average-power percentage based on charging history or a reliable test at a similar temperature can be more accurate than the generic profile.
Charging cost may include more than a price per kWh
- the home electricity rate, off-peak tariff or public-network price per kWh;
- a fixed connection or session fee;
- a per-minute charging or occupancy fee;
- parking, idle fees, taxes or minimum charges that must be added separately when they are not included in the entered rate.
The currency is not converted. Choose USD, CAD, GBP, AUD, EUR or UAH and enter every rate and fee in the same currency. This keeps the calculator usable across several markets without relying on a tariff that may become outdated.
Use miles or kilometres and either efficiency format
Regional EV efficiency formats supported
| Format | Example | Often seen in |
|---|---|---|
| kWh per 100 miles | 29 kWh/100 mi | US fuel-economy information and some charging comparisons |
| miles per kWh | 3.5 mi/kWh | US and UK dashboards, owner reports and trip planning |
| kWh per 100 kilometres | 18 kWh/100 km | Canada, Australia, Europe and metric vehicle specifications |
| watt-hours per mile or kilometre | 290 Wh/mi or 180 Wh/km | Tesla-style owner data and Australian official vehicle information |
| kilometres per kWh | 5.6 km/kWh | Metric dashboards and manual calculations |
A 75 kWh usable battery charges from 20% to 80% on a 7.7 kW AC charger. Efficiency is 90% and electricity costs 0.18 USD/kWh. What is the first estimate?
Answer: The battery needs 45 kWh. Approximately 50 kWh must be drawn from the grid, so the electricity portion costs about 9 USD. Charging time is longer than the simple 45 ÷ 7.7 calculation because grid losses and average delivered power are treated separately.
Explanation: The calculator distinguishes energy stored in the battery from metered electricity and lets the average power fall below the charger nameplate rating.
What most affects the accuracy of an EV charging estimate
- usable battery capacity and the real starting state of charge;
- the onboard AC charger limit or maximum DC acceptance of the vehicle;
- battery temperature and whether preconditioning is active;
- charging-power taper above roughly 80–90%;
- grid-to-battery losses and energy used by vehicle systems;
- the actual utility tariff, public-network fees and billing increments;
- weather, speed, tyres, heating or air conditioning and driving style when range is estimated.
This calculator does not determine whether a home electrical service, consumer unit, breaker panel, circuit or cable can support EV charging. New fixed charging equipment should be designed and checked by a qualified electrician under the rules that apply where it is installed.