Home charging vs public charging
The default electricity price above assumes charging mostly at home on a standard domestic tariff. If you're on a dedicated EV or overnight tariff, your effective per-kWh price for charging can be considerably lower — sometimes under half the standard rate. Conversely, if you rely heavily on public rapid or motorway charging, the per-kWh price can be two to three times higher than a home tariff, which meaningfully changes the comparison. It's worth running this calculator with a couple of different electricity price assumptions to see the range.
Does the comparison change with higher mileage?
Yes — the running-cost saving from an EV scales with distance driven, since it's a per-mile saving multiplied by miles. A high-mileage driver doing 15,000–20,000 miles a year on mostly home charging tends to see a substantially larger annual saving than a low-mileage driver doing 4,000–5,000 miles, simply because there's more distance for the per-mile saving to apply to. This calculator doesn't include the purchase price difference between an EV and an equivalent petrol car, servicing cost differences (EVs typically cost somewhat less to service), or insurance differences, which can also favour or work against an EV depending on the specific cars being compared.
Frequently asked questions
Does this include the price difference between buying an EV and a petrol car?
No — this tool only compares ongoing running costs (fuel/electricity), not the purchase price, which can differ significantly between an EV and its petrol equivalent.
What miles-per-kWh figure should I use?
Most modern EVs achieve somewhere between 2.5 and 4.5 miles per kWh depending on the car, driving style and time of year (efficiency drops in cold weather). Check your specific model's typical real-world figure if you can find one, rather than relying on the official WLTP range figure alone.
Does this account for public rapid charging costs?
Only if you set the electricity price field to reflect your actual mix of charging — try entering a blended average, or run the calculation twice with a home price and a public price to see both ends of the range.