Advanced options
What The EV Charging Cost Calculator Works Out
- Energy delivered: battery size multiplied by the percentage added, then grossed up for charging losses (the electricity that becomes heat rather than stored charge). Taking a 60kWh battery from 20% to 80% stores 36kWh but draws about 40kWh from the socket.
- Cost at home: kWh drawn multiplied by your home unit rate. The default is the current Ofgem price cap rate, which makes the example charge roughly GBP 10; home electricity carries 5% VAT.
- At a public rapid charger: the same energy at a rapid or ultra-rapid rate, typically 70p to 90p per kWh and carrying 20% VAT, which puts the same charge over GBP 30. Slower lamppost and destination chargers often sit in the 40p to 60p range.
- Charging losses (advanced): override the 10% default. Slow 3-pin charging loses more (15% or so), DC rapid charging slightly less, and cold weather adds to both.
- Car's efficiency (advanced): miles per kWh, typically 3 to 4 for most EVs, lower for big SUVs and in winter. It turns the energy stored into the "range added" card: the 20% to 80% example adds roughly 120 to 145 miles.
- Cost per mile (advanced): the charge cost divided by the range it adds, shown for home, public and off-peak rates. Home charging on the right tariff works out around 2p to 3p a mile, far below petrol at 12p to 20p.
- Off-peak EV tariff (advanced): what the same charge costs on a dedicated EV tariff, where overnight rates of around 7p per kWh cut the example charge to under GBP 3. The sub-line shows the saving per charge against your standard rate.
- Annual charging cost (advanced): charges per month multiplied by twelve, blending home and public costs by the share of charging you do at public rapids. Drivers without off-street parking who rely on public charging can pay several times more a year.
- Same miles in a petrol car (advanced): the yearly miles those charges add, run through a petrol car at the mpg you enter and the current average pump price, with the annual saving (or extra) alongside. Insurance, servicing and depreciation sit outside this comparison.
Source and further reading: Ofgem: energy price cap.