EV Home Charging Tariff Calculator
Compare a single-rate electricity tariff against a cheap overnight EV tariff for charging your car at home — see the annual saving, and how it stacks up honestly against the petrol equivalent.
Estimate only. These are estimates based on the figures you enter — actual tariff rates, standing charges and driving patterns vary. This does not include electricity standing charges, or the cost of the vehicle itself.
Moving your charging to an EV off-peak tariff saves this much a year compared with your single-rate tariff.
Annual charging: 2114.3 kWh — 1797 kWh off-peak + 317 kWh day rate
| Tariff | Annual cost |
|---|---|
Single-rate tariff | £518 |
EV off-peak tariffCheapest | £208 |
Petrol equivalent | £1,219 |
The same 7,400 miles a year in a petrol car (at 40mpg, 145p/litre) would cost £1,219 — petrol works out about 5.9x more expensive than your EV off-peak tariff.
- Off-peak windows are usually fixed hours (e.g. midnight-7am) — you'll need a smart charger, or your car's own scheduled-charging setting, to reliably charge in that window rather than as soon as you plug in.
- Check the tariff's standing charge as well as the unit rates — some EV tariffs have a higher daily standing charge that can eat into the saving if you don't drive many miles.
- Public rapid and ultra-rapid charging is priced per kWh at a much higher rate than home charging — relying on it regularly can wipe out most of the saving shown here.
- If you can shift other big loads (like a washing machine or dishwasher) into the same off-peak window, the saving from switching tariff goes further than charging alone.
How this comparison is worked out
Annual charging need (in kWh) is your annual mileage divided by your car's efficiency in miles per kWh. On a single-rate tariff, every kWh costs the same. On an EV off-peak tariff, the share of charging you do overnight is billed at the cheap off-peak rate, and the rest at the tariff's day rate — this calculator splits your annual kWh by the percentage you tell it is done off-peak, and totals the cost on each side. The petrol comparison applies the same mileage to a petrol car at your chosen fuel economy and pump price, using the same maths as the site's Fuel Cost Calculator, so you can see the full picture — not just the EV tariff saving, but how driving on electricity compares with driving on petrol at all.