The real cost of 100 km on electricity vs petrol and diesel
We explain how to work out your own accurate cost comparison between charging and fuel, instead of relying on someone else's generic claim with no numbers behind it.
"How much will I actually save" is the first thing almost every prospective EV buyer calculates. The answer depends heavily on how you charge, so the most useful thing is understanding the method — not relying on someone else's generic number.
The formula for an EV
Cost per 100 km is calculated as:
(consumption kWh/100km) × (price per kWh) = cost per 100 km
Consumption varies by model, driving style, and temperature — typically between 14 and 22 kWh/100km for city and mixed driving.
Differences by charging location
Home overnight charging is the cheapest option — on an off-peak tariff, the cost per 100 km is significantly lower than the daytime rate. This is where the real savings against fuel are the biggest.
Public AC charging (11-22 kW) usually costs more than home charging but remains cheaper than fast DC charging.
Public DC fast charging is the priciest way to charge an EV — relying mostly on DC stations for frequent long trips can seriously narrow the advantage over fuel.
The formula for a combustion car
(consumption L/100km) × (price per liter of fuel) = cost per 100 km
Typical consumption for a mid-size car is 6-8 L/100km for petrol, 5-6.5 L/100km for diesel in mixed driving.
How to run your own numbers
For an accurate comparison, use your actual consumption (not the optimistic factory WLTP figure), your current electricity price on your tariff, and the current fuel price at the station you normally use. Factory EV consumption figures tend to be closer to real-world use than WLTP fuel figures, but it's still worth checking against your own driving style.
An important caveat
Charging savings are only one part of the total cost picture. For the full picture, add the difference in maintenance (fewer moving parts in an EV), tax breaks, and insurance costs to get the real annual expense.
Conclusion
There's no single universal savings figure — it depends entirely on your charging pattern. An owner charging mostly at home overnight will save significantly more than one relying mainly on expensive DC stations.
Browse EVs on FindVolta and run your own numbers before buying.