How much does an EV cost per 100 km? Calculate electricity costs
The electricity cost of driving an electric car depends on how many kWh it uses and what you pay for charging. Instead of assuming every EV costs the same to run, calculate the cost of 100 km with the consumption of your own car and the price you actually pay.
The formula: from battery consumption to the electricity bill
Battery consumption in kWh/100 km describes the energy the car uses. The charger often draws more from the grid because of charging losses. Voltavena treats losses as a share of grid energy: electricity purchased = battery consumption ÷ (1 − loss percentage / 100). Electricity cost per 100 km = purchased kWh × price per kWh. Cost per kilometre is the result divided by 100.
Worked example with the Voltavena calculator
Assume 18 kWh/100 km at the battery and 8% charging losses. The electricity price below is an illustrative national input, not a live rate. The alternative public-charging scenario simply doubles that example kWh price, without any session fees.
- Battery use per 100 km
- 18 kWh
- Grid electricity per 100 km
- 19.57 kWh
- Illustrative electricity price
- €0.30/kWh
- Electricity cost per 100 km
- €5.87
- Electricity cost per km
- €0.06
- Scenario at twice the kWh price
- €11.74
The numbers are generated with the same calculation function used by the calculator. A doubled price is only a hypothetical comparison, not an actual public charger tariff. Rounding the displayed result does not change the formula.
Which electricity price should you enter?
For home charging, estimate the full marginal kWh price that applies to your charging, including relevant variable network charges and taxes. For public charging, use the actual price in the charging app or operator tariff; card fees, session fees and time-based charges may be separate. If you regularly use multiple charging methods, calculate different scenarios or use the charging-mix calculator.
How do weather, speed and charging losses affect the result?
A higher kWh/100 km consumption makes every 100 km more expensive, even if the electricity price stays the same. Speed, temperature, heating, tyres and terrain may change real consumption. Charging losses describe energy between the grid and the battery, not battery wear. This example applies one loss percentage; actual losses differ between chargers and situations.
What this estimate does not include
This is an electricity-only comparison. It does not include a car purchase, depreciation, financing, insurance, maintenance, road tax, parking, a home wallbox or charging subscriptions. Session or idle fees are also not included in this specific per-100-km formula. Example electricity prices are not current or official tariffs; replace them with your own.
Frequently asked questions
Is the cost per 100 km the same as a full ownership cost?
No. The calculation covers electricity purchased for driving. Ownership also involves depreciation, insurance, servicing, taxes and other costs. See the annual-cost calculator for a wider estimate.
Why is purchased electricity greater than battery consumption?
Some energy is lost during charging. With 8% loss measured relative to grid energy, the car receives 92% of purchased electricity. Divide battery consumption by 0.92 rather than adding 8% to battery use.
Can I use a public fast-charging price?
Yes. Replace the electricity price with the tariff that applies to you, but remember that start fees, time charges, parking and subscriptions are not included in this particular calculation.