The EV sales pitch has a line that gets repeated so often it's become accepted wisdom.

"Electric is cheaper to run than petrol or diesel."

It's on every manufacturer's website. It's in every government leaflet about the 2035 combustion engine ban. It's what enthusiastic EV owners tell their sceptical friends at dinner parties.

And like most things that get repeated often enough to become conventional wisdom, it's only partially true.

The reality is more nuanced, more interesting, and more important to understand before you make a decision that costs you tens of thousands of pounds. So let's do what we always do here and look at the actual numbers honestly.

FIRST, THE FUEL COST COMPARISON

Let's start with what the headline claim is based on, because it isn't wrong exactly — it's just incomplete.

At the time of writing, petrol in the UK is averaging around 142p per litre. A reasonably efficient petrol car — say a Ford Focus or similar — does around 40 to 45 miles per gallon in real world driving. A gallon is 4.55 litres, so filling 250 miles worth costs roughly £16.25 to £18.13 in fuel. That works out to around 6.5p to 7.2p per mile.

Diesel is marginally cheaper per litre right now and more efficient, so a good diesel — 55 miles per gallon real world — comes out at around 5.5p to 6p per mile. For 250 miles that costs between £13.75 to £15

Now the EV side. My Kia EV5 uses around 3 to 3.5miles of range per kWh in real world mixed driving. The standard domestic electricity rate in the UK is currently around 24p per kWh. At that rate, electricity costs me roughly 6.9p to 8p per mile. For 250 files this would cost between £17.25 to £20

At standard domestic electricity rates, an EV is actually more expensive than fuel.

Most EV owners overcome this by switching to a cheaper overnight tariff such as Octopus Intelligent Go which I use.

This is where the equation changes significantly.

I'm on Octopus Intelligent, an EV specific overnight tariff that gives me electricity at around 7p per kWh between 11:30pm and 05:30am. My car charges overnight during those hours automatically. I wake up every morning with a full battery that cost me a fraction of what standard rate electricity would have.

At 7p per kWh and 3 to 3.5 miles per kWh real world, I'm paying roughly 2p to 2.3p per mile to charge at home overnight. For 250 miles, this would cost £5 to £5.75.

That is dramatically cheaper than petrol or diesel. At that rate the EV running cost advantage is real, significant, and meaningful over the course of a year. If I drive 15,000 miles annually but am always able to charge at home and considering the lowest fuel prices:

The saving is real. But it depends entirely on one thing — having a home charger.

IF YOU CAN'T CHARGE AT HOME, THE NUMBERS LOOK VERY DIFFERENT

This is the conversation the EV industry quietly avoids.

If you live in a flat, a terraced house with no off street parking, or anywhere else that makes home charging impossible, you are entirely dependent on the public charging network. And the public charging network does not price like a home charger.

Rapid chargers — the 50kW to 150kW units you find at motorway services and dedicated charging hubs — typically charge between 65p and 85p per kWh at the moment. Some premium locations are higher.

At 75p per kWh and 3.8 miles per kWh, you're paying around 20p per mile for electricity. That is not cheaper, it is far more expensive than petrol.

Ultra rapid chargers at 150kW to 350kW — the fastest available — often price even higher. The convenience of speed costs money, just like a motorway service station forecourt costs more than a supermarket fuel pump.

If you are entirely dependent on rapid public charging, an EV is not cheaper to run than a petrol equivalent. It may be considerably more expensive.

If you use a fast charger at 80p per kWh, 250 miles would cost £57.14 to £66.67.

THE RANGE AND FILL UP COMPARISON

There's another dimension to this that affects the real cost calculation — how far you can go before stopping.

A petrol Ford Focus with a 47 litre tank does around 400 to 450 miles on a full tank in mixed driving. A diesel equivalent stretches to 500 miles+. My BMW 520d does 700 miles to a tank of diesel. Filling up takes four minutes.

My EV5 does around 240 to 260 miles in mixed real world conditions before needing a charge. Charging from low to full at home overnight takes seven to eight hours — but costs almost nothing and requires zero effort from me. Charging from 20 to 80 percent at a rapid public charger takes around 25 to 35 minutes.

The range gap is real and relevant for long journeys. For daily driving — the school run, the supermarket, the commute — the vast majority of EV owners never come close to the limit of their range. The fill up comparison only matters if you regularly drive long distances without returning home.

For most people, most of the time, waking up to a full battery every morning is actually more convenient than a petrol car. You never visit a fuel station. You never watch numbers click upward on a pump. Your car is always ready.

For people who regularly drive 300 plus miles in a day, the calculus is different and worth thinking through carefully before switching.

THE HONEST VERDICT

Here's the framework I'd give anyone asking whether an EV will be cheaper to run:

If you can charge at home and you're on or can get onto an EV overnight tariff like Octopus Intelligent Go, an EV will be significantly cheaper to run than petrol or diesel. The savings are real and they compound meaningfully over time.

If you can charge at home but only at standard domestic rates, an EV is roughly the equivalent of petrol and slightly more expensive than a good diesel.

If you cannot charge at home and rely primarily on public rapid charging, an EV may well cost you a lot more to run than a petrol equivalent. The public network pricing makes the economics work against you, and that's a fact the industry doesn't advertise.

The home charger is not optional if the economics are to make sense. It is the foundation on which the entire running cost argument is built.

Ask that question before anything else. Can I charge at home? Everything else follows from the answer.

Financially, EV’s work for many people but it does depend on your circumstances and what you use your EV for.

Matt
Charging Up
chargingup.uk

P.S. Can you charge at home, or are you reliant on public charging? Hit reply and let me know — it shapes everything about whether an EV makes financial sense for you and I'd love to know the split among Charging Up readers.