Charging an electric car at home is cheap — but how cheap depends almost entirely on one thing: whether you are on a dedicated overnight EV tariff. On the right tariff you are looking at about 2p a mile. On the standard price cap it is nearer 7.5p. Both beat petrol, but the gap between them is the difference between a car that costs £160 a year to fuel and one that costs £600.
The cost per mile, four ways
Assuming a fairly typical EV doing 3.5 miles per kWh, here is what each way of charging costs at the Ofgem cap for 1 July – 30 September 2026 — with petrol at 45mpg and 135p a litre for comparison, over a typical 8,000 miles a year:
| How you charge | Per mile | 8,000 miles / year |
|---|---|---|
| Home, overnight EV tariff (7p) | 2.0p | £160 |
| Home, standard cap rate (26.11p) | 7.5p | £597 |
| Petrol equivalent (45mpg, 135p/litre) | 13.6p | £1,091 |
| Public rapid charger (79p) | 22.6p | £1,806 |
The order of that table is the whole story. Overnight home charging is transformative. Standard-rate home charging is still clearly cheaper than petrol. But public rapid charging can cost morethan filling a petrol tank — which is why an EV's running-cost case rests on being able to charge at home most of the time.
What it costs to fill up from empty
For a common 60 kWh battery, charging from empty draws around 66 kWh once you allow for roughly 10% charging losses (home AC charging is not perfectly efficient). At 7p overnight that is about £4.60; at the standard 26.11p cap rate it is about £17. That single charge might cover 200 miles — so even at the dearer rate you are paying roughly 8.5p a mile, against 13.6p for petrol.
Getting to the 2p-a-mile figure
The cheap number is not automatic. To hit it you need three things lined up:
- A time-of-use EV tariff with a cheap overnight window (typically 7p or so for a few hours at night).
- A home charger or a way to schedule charging so the car pulls its power inside that window.
- Enough off-street parking to charge overnight rather than relying on public chargers.
Without off-street parking the sums change a lot, because you lean on public charging where the per-mile cost can rival or beat petrol. That is the honest catch behind the headline: the dramatic EV savings are real, but they assume home charging on a good tariff. If that is not your situation, run the numbers on your actual mix before assuming an EV will be cheaper to fuel.
Solar makes it cheaper still
If you have solar panels, daytime charging can use electricity that would otherwise export for around 15p a unit — effectively free miles in summer. It only works if the car is home during the day and the sun is out, so it complements an overnight tariff rather than replacing it. Worth a look if you are weighing panels anyway: see whether solar is worth it where you live.