Petrol Just Spiked. Your Electricity Bill Just Fell. Let Me Explain.

Two things happened this month that, individually, would each be a reasonably interesting blog post. Together, they've moved the EV-vs-petrol number more than anything I've written about all year, and almost nobody seems to have noticed both at once. So let's do both at once.

Thing one: petrol and diesel got noticeably more expensive, fast. Thing two: the Ofgem price cap — the thing that sets the default electricity rate most people are quietly paying — went down. Petrol up, electricity down, in the same fortnight. If you've been charging at home, this is the best month for your running costs in a while. If you've been relying on public rapid charging, it is very much not, and I want to be honest about that part too.

What actually happened

Two unrelated markets, two regulators, one coincidence of timing. I don't think anyone planned this. I do think it's worth doing the actual sums instead of just vibing about it, which is usually where this kind of story ends up on social media.

The home-charging number got better. Noticeably.

At the new 26.1p/kWh rate, a typical EV doing 3.5 miles/kWh costs about 7.5p per mile to charge at home. A petrol car doing 40 MPG now costs about 17.4p per mile at the new pump prices. That's a gap of just under 10p per mile — call it £990 a year at 10,000 miles, up from roughly £800 back in June. Nobody did anything differently. The market just moved in the EV owner's favour twice in the same month.

For anyone still on the fence about whether to make the switch, this is about as good as the headline comparison has looked all year. I ran the calculator with current prices and my own commute, and the number moved enough that I went and checked it twice, which is not something I usually admit to doing in public.

The bit nobody's writing headlines about: public charging got worse

Here's the part that gets left out of the celebratory version of this story. Public rapid and ultra-rapid charging averaged 79p/kWh across UK networks in mid-2026 — up sharply from where it sat a couple of years ago, and a much bigger jump than either petrol or the electricity cap moved this month. At 79p/kWh, an EV doing 3.5 miles/kWh costs about 22.6p per mile. That is more expensive than a 40 MPG petrol car, not competitive with one.

I did the maths on this properly for the EV vs diesel guide and the result surprised me: once public charging makes up half your miles or more, a diesel now works out cheaper than an EV, which was not true a year ago. Home charging isn't just the cheaper option any more — for a lot of driving patterns, it's the only option that still makes the EV case at all.

The cheapest network, Tesla Supercharger, is still down around 62p/kWh. The most expensive PAYG rates on InstaVolt and BP Pulse sit nearer 90p/kWh. If you're charging in public regularly, which network you use has become a genuinely large chunk of your annual running cost — not a rounding error.

So what should you actually do with this

If you can charge at home, this month is a genuine, measurable improvement in your running costs and there's nothing more to it than that. Enjoy it. If you can't charge at home and you've been assuming public rapid charging keeps you roughly petrol-competitive, it's worth checking that assumption now rather than at your next service. It may no longer be true, and for some driving patterns it has flipped outright.

Either way, national averages hide a lot. Your own numbers depend on your mileage, your tariff, and how much of your charging actually happens at home versus on the road. That's what the calculator is for — I'd rather you ran your own figures than trusted my averages.