EV vs Gas Calculator: TCO and Cost per 100 km

Compare an electric car with a petrol or diesel one: cost per 100 km with off-peak, peak or fast charging, yearly savings and total cost of ownership over 3 to 8 years.

Total cost of ownership, electric vs combustion: the method

Total cost of ownership (TCO) adds up, over the holding period, the purchase price net of incentives, minus the estimated resale value, plus energy, maintenance and insurance for each year. With the default settings (18,000 km a year for 5 years), the electric car costs €24,470 against €37,913 for the combustion car, i.e. €0.27 versus €0.42 per km.

The formula

TCO = (purchase price − incentive, or + registration and CO₂ penalty for the combustion car) − residual value + (energy + maintenance + insurance) × years. Residual value is the gross purchase price × 0.86 per year of ownership for the electric car (47% after 5 years) and × 0.85 for the combustion car (44%). The average kWh price blends off-peak home charging and fast chargers according to the share chosen.

Worked example (default values)

  • Electric: €38,000 − €4,000 incentive; 16.5 kWh/100 km; 80% at €0.1592/kWh and 20% at €0.49/kWh, i.e. €0.2254/kWh and €3.72/100 km; maintenance €250, insurance €750 a year.
  • Combustion: €33,000 + €800; 6.8 L/100 km at €1.88/L, i.e. €12.78/100 km; maintenance €650, insurance €800.
  • Energy per year: €669 against €2,301. Running-cost saving: €2,082 a year.
  • Residual values: €17,876 and €14,642. 5-year TCO: €24,470 against €37,913, a €13,443 gap. The €200 purchase premium is recovered in 0.1 years.

Assumptions and limits

  • Depreciation rates, maintenance, insurance and the fast-charging price (€0.49/kWh, not regulated) are the tool's reference figures, not verified. The €1.88/L fuel price is a starting value: check today's price on prix-carburants.gouv.fr.
  • The €4,000 incentive is indicative: the French "coup de pouce" for electric cars, funded by energy-saving certificates since 1 July 2025, depends on income and on the energy supplier's offer. The tool ignores loans and charger installation.
  • CO₂ avoided uses 160 g/km against 25 g/km (indicative values).

Charging is split between off-peak, peak (€0.2145/kWh) and fast charging; if the three shares do not add up to 100%, the tool scales them to their sum. The cost per 100 km is also compared with a diesel (5.5 L at €1.78/L, i.e. €9.79), alongside the TCO. This is an estimate and does not replace advice from an adviser.

Sources and dates: French regulated off-peak rate ≤ 6 kVA on 01/08/2026: 10.18 c€/kWh excl. tax (CRE decision 2026-147, annex B) + excise €30.85/MWh from 01/02/2026 (BOFiP, BOI-RES-EAT-000240) + 20% VAT = €0.1592/kWh; Service-public, electric passenger vehicle boost (page checked 09/10/2026) (checked 14/10/2026)

Frequently Asked Questions

Is an electric car cheaper to own than a combustion car?

With the default settings (18,000 km a year for 5 years), the tool finds €24,470 for the electric car against €37,913 for the combustion car. Most of the gap comes from energy: €669 against €2,301 a year.

How long does it take for an electric car to pay off?

The tool divides the purchase premium, after incentives, by the yearly running-cost saving. With a €200 gap and €2,082 saved a year, the electric car pays off in 0.1 years; with a €5,000 gap it would take about 2.4 years.

Which kWh price should I use for home charging?

On 1 August 2026, the French regulated off-peak rate (6 kVA) comes to €0.1592/kWh incl. tax and the Base option to €0.2003/kWh. The tool starts from €0.1592/kWh for off-peak home charging and €0.2145/kWh at peak times.

What help is there to buy an electric car in France in 2026?

The ecological bonus was replaced on 1 July 2025 by the "coup de pouce" for electric passenger cars, funded by energy-saving certificates. The amount depends on household income and on the supplier paying it; the tool suggests €4,000 by default, to be adjusted.

How much does 100 km cost in an electric car?

With 16.5 kWh per 100 km and an average price of €0.2033/kWh (70% off-peak, 20% peak, 10% fast charging), the tool finds €3.36 per 100 km. Charged only at fast chargers at €0.49/kWh, the same car costs €8.08.

Does off-peak charging really make a difference?

Yes: on 1 August 2026 the French regulated rate comes to €0.1592/kWh incl. tax off-peak against €0.2145 at peak times (6 kVA). For 16.5 kWh per 100 km, that is €2.63 against €3.54.

Is an electric car cheaper per kilometre than a diesel?

With the default settings, yes: €3.72 per 100 km against €9.79 for a diesel using 5.5 L at €1.78/L. Over 18,000 km a year, the energy gap reaches €1,093.

Why does my cost per 100 km look too high?

Look first at the fast-charging share: at €0.49/kWh, fast chargers cost three times the off-peak price. By default (80% off-peak, 20% fast charging) the average price is €0.2254/kWh; with 60% off-peak, 10% peak and 30% fast charging it rises to €0.2640/kWh. Shares that do not add up to 100% do not skew the result: the tool scales them to their sum.

Is this tool really free?

Yes, all tools on Kristools are 100% free and accessible without registration.

Is my data protected?

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