EV Charging Cost Calculator

What is the EV Charging Cost Calculator?

An EV charging cost calculator works out how much it costs to charge an electric vehicle at home, based on the battery's capacity, your electricity price per kWh, and the charge range you're topping up (for example, from 20% to 80%). It works by calculating the energy needed to cover that percentage range of the battery's total capacity in kWh, then multiplying by your price per kWh (converted from pence to pounds). To calculate it manually: kWh needed = battery size × (target% − current%) ÷ 100, then cost = kWh needed × price per kWh ÷ 100 — home EV/off-peak tariffs can be significantly cheaper overnight than standard rates, and public rapid chargers are typically priced higher per kWh than charging at home.

How it works

Charging cost is simply the energy added to the battery (in kWh) multiplied by your electricity price per kWh. The energy added is your battery's total capacity multiplied by the percentage-point gap between your starting and target charge level.

UK context

Home charging is generally far cheaper per mile than running a petrol or diesel car, especially if you're on an EV-specific or off-peak electricity tariff, which can offer significantly lower rates for overnight charging. Public rapid and ultra-rapid chargers are typically priced considerably higher per kWh than home charging, since you're paying for speed and convenience — worth factoring in if you rely on public charging regularly.

Tips

• Check whether your energy supplier offers an EV-specific or off-peak tariff — scheduling charging overnight can meaningfully reduce your cost per charge.
• Public rapid charger pricing varies a lot by network and location — check the app or network's pricing before relying on public charging for routine top-ups.
• Charging efficiency (some energy is lost as heat during charging) means the energy that actually reaches the battery is slightly less than what you're billed for — a small but real factor in the true cost per mile.

A quick note

Uses the electricity price and charge range you enter — actual home tariffs vary, especially with EV/off-peak tariffs, and public charging is typically priced differently from home charging.