02 / EV energy-cost planning

Know what your
charging mix really costs.

Compare home and public charging with petrol or diesel. Include energy losses, your monthly driving and extra charging fees—not just a battery-size multiplication.

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Your car and driving

Display currency

Labels only; no exchange-rate conversion.

Usable battery capacity (kWh)

Starting charge (%)

Target charge (%)

Monthly distance (km)

Battery-side use (kWh / 100 km)

Use onboard/battery consumption. A wall-meter figure already includes charging losses.

Where you charge

All tariffs below are editable examples, not live market prices. Use an all-in billed price per kWh.

Home price (currency / kWh)

Public price (currency / kWh)

Home charging efficiency (%)

90% means 10% of billed energy is lost.

Public billed-energy efficiency (%)

Use 100% when the billed energy equals energy delivered into the battery.

Share of energy charged at home (%)

Extra charging fees per month

Include subscriptions or other recurring charging fees.

Home AC charger power (kW)

Car AC charging limit (kW)

Compare with petrol or diesel

Fuel price (currency / litre)

Fuel consumption (litres / 100 km)

Energy cost only. Vehicle purchase price, insurance, charger installation, tax and maintenance are not included.

Compare the same energy basis

Battery energy is not always the same as billed energy. The calculator makes that assumption visible, so charging losses are not silently ignored or counted twice.

Session kWh = usable battery kWh × charge-level change
Billed kWh = battery kWh ÷ billed-energy efficiency
Monthly EV cost = km ÷ 100 × blended energy cost + monthly fees

Public break-even is the per-kWh public price that matches fuel cost per 100 km, before subscriptions. AC charge time is an idealised estimate using the lower of charger power and the car’s AC limit.

Reference: ADAC: measured charging losses and variation by charging method.

Guide: when public charging stops saving money →

Assumptions that matter

Are these current electricity or fuel prices?

No. Every starting price is an illustrative input. Replace it with your own all-in tariff. The application has no live feeds, country tax engine or energy-provider database.

What about per-minute and session fees?

Convert them into an effective billed price per kWh for a representative session, or include them in the monthly extra fees. Do not count the same fee twice.

What can the time and savings estimates miss?

Charge tapering, cold-weather conditioning, varying consumption and price changes can alter real results. Annual saving simply repeats the entered month twelve times; it is not a forecast or total ownership comparison.