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EV · Flagship calculator

EV Charging Cost Calculator

Cost per charging session, per 100 km, per year — plus savings versus petrol and CO₂ avoided. Uses charger efficiency, a blended home/public tariff and real-world consumption, so the numbers match your bill rather than the manufacturer brochure.

Your car & tariff

Presets are 2025 residential averages. Pick "Custom" to override any field individually.

Small EV 40 · mid 60–75 · large 90–110 · truck/SUV 130–200.

Small 14–17 · mid 16–20 · SUV 20–28. Add 20–35% in winter.

20%
80%

Home 3.7 / 7.4 / 11 / 22 kW · public DC 50 / 150 / 350 kW.

AC home 85–92% · DC rapid 90–95%.

80% home · 20% public

Typical home driver: 80–90% home. High-mileage commuter without home charging: 20–40% home.

EU avg 0.23 · UK 0.19 · Norway 0.02 · US 0.37.

Cost per 100 km

€7.36

20.5 kWh/100 km at meter · blended €0.36/kWh.

Charging session (20% → 80%)

€14.73

36 kWh into battery · 40.9 kWh billed at meter.

Charge time

4.9 h

At 7.4 kW steady delivery. Real DC sessions taper above 80%.

Annual running cost

€1,105

3,068 kWh/year for 15,000 km.

Savings vs petrol / year

€650

Petrol cost €1,755 − EV cost €1,105.

CO₂ avoided / year

1,332 kg

Petrol 2,252 kg − EV 920 kg (grid at 0.3 kg/kWh).

How the math works

EV running cost is a chain of five multiplications. The tricky part is charger efficiency — the kWh your meter records is not the kWh that reaches the battery — and the blended tariff between cheap home charging and expensive public rapid sessions:

Energy per session = battery × (target% − start%) ÷ efficiency

Charge time = energy into battery ÷ charger power

Blended price = home% × home price + public% × public price

Cost per 100 km = consumption ÷ efficiency × blended price

Annual cost = km ÷ 100 × cost per 100 km

Real-world consumption matters more than any other input. Manufacturer WLTP figures are typically 10–25% below what you actually see on the trip computer, and winter driving with cabin heating adds another 20–35% on top. Use the number from your car, not the brochure.

Blended tariff is the second-largest driver. Home charging at 0.20 €/kWh vs public rapid at 0.65 €/kWh is a 3× spread — so the home-vs-public share swings annual cost by hundreds of euros. Drivers with a home wallbox routinely spend a third of what they would on rapid-only charging.

CO₂ avoided depends on your grid intensity. In Norway (~50 g/kWh) an EV emits under 5% of petrol CO₂ per km; on a coal-heavy grid the ratio narrows but stays favourable because EVs are 3–4× more efficient at the wheels than a combustion engine.

Frequently asked questions

How is EV charging cost actually calculated?
Cost per session equals the energy delivered to the battery divided by charger efficiency, multiplied by your electricity price. Cost per 100 km is your car's consumption (kWh/100 km) divided by charger efficiency, multiplied by the blended price of home + public charging. This calculator does both and then annualises them using your driving distance and home/public split.
Why does charger efficiency matter?
AC home chargers lose 8–15% of drawn energy to the onboard charger, cables and battery thermal management. DC rapid chargers lose 5–10%. This means the kWh your meter records is 10–20% higher than the kWh that reaches the battery — and you pay for the meter reading, not the battery reading. The default 88% efficiency reflects a typical mixed real-world scenario.
What consumption should I enter (kWh/100 km)?
Manufacturer WLTP figures are usually optimistic by 10–25% in real driving. Typical real-world numbers: small EVs 14–17 kWh/100 km, mid-size 16–20 kWh/100 km, SUVs and performance cars 20–28 kWh/100 km. Add 20–35% for winter driving with cabin heating. Check your car's trip computer for the truth.
How long does it take to charge from 20 to 80%?
Energy needed = battery capacity × 60% ÷ charger efficiency. Time = energy ÷ charger power. Example: a 60 kWh battery on a 7.4 kW home charger needs (60 × 0.6 ÷ 0.88) ÷ 7.4 ≈ 5.5 hours. On a 150 kW DC rapid charger the same 20–80% window takes roughly 25 minutes because the average delivered power is around 90 kW after tapering.
Is a home charger always cheaper than public rapid charging?
Yes — typically 2–4× cheaper per kWh in Europe and the US. Home tariffs of 0.15–0.30 €/kWh compare to public rapid at 0.45–0.80 €/kWh. Even accounting for the €500–1,500 installation of a home wallbox, break-even is usually reached within 12–18 months for a driver covering 10,000+ km per year.
Does the calculator include battery degradation?
No. Modern EV batteries lose 1–2% capacity per year and are typically warranted at 70% of original capacity for 8 years or 160,000 km. Degradation reduces range but does not change cost per kWh, which is what this calculator computes. Multiply annual cost by a small correction if you want to model reduced range from a smaller usable battery.
How does the petrol comparison work?
For each region the calculator uses a typical petrol pump price and a reference consumption you enter (default 6.5 L/100 km for a mid-size petrol car, or 30 US MPG). Annual petrol cost = km ÷ 100 × L/100 km × price per litre. The savings figure is your annual petrol cost minus your annual EV charging cost. CO₂ avoided uses 2.31 kg per litre of petrol vs your grid intensity per kWh consumed.

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