UK EV Tariffs Explained 2026: Real Savings, Not Just the 7p Headline

The belief most new EV drivers have about home tariffs

Most people who buy an electric car arrive at the EV tariff question the same way. They see a headline rate of around 7p per kWh, compare it with the cap at 24.67p, and assume their charging bill is about to fall by two thirds. The advert is true. The conclusion is not.

An EV tariff is not a discount on all your electricity. It is a time-of-use (TOU) tariff, which means it splits the day into windows. The cheap window is short, often four to seven hours overnight, and only charging that lands inside that window earns the 7p headline. Everything else, including running the dishwasher at 8pm or topping up the car after a Sunday drive, is billed at the peak rate. That peak rate is usually higher than the cap, not lower.

The off-peak rate is one of three numbers that decide whether the tariff actually saves you money. The other two are the peak rate (which most suppliers raise above the cap to fund the cheap window) and the standing charge (the fixed daily fee you pay just to stay connected, currently 57.21p per day under the Ofgem cap).

If you charge your EV exclusively inside the off-peak window, the tariff works as advertised. The moment you slip out of that window for any meaningful share of charging, or the moment a chunk of your normal household electricity sits at the peak rate, the maths gets a lot tighter. The kWh, or kilowatt-hour, is the unit you actually pay for; the rate per kWh just tells you how much each one costs at each time of day.

Why most EV-tariff comparisons get the maths wrong

Most online guides compare an EV tariff to the cap using only the off-peak unit rate. They assume 100 percent of your charging happens overnight and ignore the peak rate entirely. That is the comparison supplier marketing wants you to do, not the one your annual bill cares about.

A second mistake is treating EV charging in isolation. An EV tariff usually applies to your whole household, not just the car. The fridge, kettle, TV and morning shower all run at the peak rate. If your home uses 2,700 kWh a year on top of the EV (the Ofgem TDCV figure for a typical UK home), most of that sits above the cap, not below it. A genuine comparison weighs three things at once: how many kWh you push into the car, the share you can shift into the off-peak window, and the peak premium you pay on everything else.

How a UK EV tariff is really built

A UK EV tariff is a regulated retail product that uses the same Ofgem metering rules as any other electricity tariff. The supplier just weights the cost across the day. Three components do all the work.

Off-peak window, peak rate and the standing charge

The off-peak window is a fixed slot, typically 23:30 to 05:30 or 00:30 to 04:30, when the unit rate drops to around 6.5p to 9.5p per kWh. Outside that window you pay the peak rate, which is usually close to or slightly above the Ofgem cap of 24.67p per kWh. The standing charge sits on top, applied every day whether you charge or not.

The supplier is allowed to recover its share of network and policy costs in either the standing charge or the unit rate. EV tariffs tend to keep the standing charge similar to the cap and front-load the trade-off into the peak unit rate. That is why a five-hour cheap window can co-exist with a 32p peak rate without breaking the cap rules.

Smart vs simple TOU: who controls the charge schedule

A simple TOU EV tariff hands you a fixed cheap window and expects you to schedule your charger to run inside it. You set the timer, the supplier bills the kWh, and nothing else changes. This works fine for most drivers but depends entirely on your discipline (and your charger's clock).

An "intelligent" or smart-controlled EV tariff goes further. The supplier integrates with your charger or car via an app, decides when to charge based on grid conditions, and gives you the off-peak rate even if charging slips outside the headline window. Intelligent Octopus Go is the best-known UK example. The trade-off is that you have to use a compatible charger or vehicle, and the supplier holds the schedule.

Where UK EV drivers actually overpay

Real bills go wrong in a few predictable ways. None of them are the supplier's fault; they are structural traps in how time-of-use tariffs interact with normal life.

Charging outside the off-peak window without realising

If the car runs low after a long trip, drivers plug in straight away. If the charger is not set to defer to the off-peak window, that charge happens at the peak rate, sometimes higher than the cap. A 40 kWh top-up at 32p costs £12.80, against £3.00 inside the cheap window. Do that twice a month and the annual saving evaporates.

The fix is to set the charger's schedule once and trust it, or move to an intelligent tariff where the supplier decides. The cheap rate is not a default; it is an opt-in.

Treating all home charging as "the EV tariff rate"

Drivers often calculate cost per mile using only the off-peak rate, even when 20 to 30 percent of charging happens at peak. That makes the EV look cheaper than it really is and skews the comparison with petrol or diesel.

The right number is the blended cost per kWh, weighted by the share of charging in each window. The calculator below does this live; plan as if the blended rate were your true charging cost, not the marketing rate.

Insider truth: the EV tariff only pays back at a certain mileage

Think of an EV tariff as a subscription you pay for in peak-rate premiums. The supplier sets the peak rate above cap so they can sell you cheap electricity overnight. The more miles you drive (and charge off-peak), the more you reclaim from that premium. Below a certain mileage, you never reclaim it all.

For a driver doing 4,000 miles a year at 3.5 miles per kWh and 80 percent off-peak charging, the EV tariff barely beats the cap once the peak premium on remaining household use is added in. At 10,000 miles a year, the same driver charges around 2,857 kWh into the car and the off-peak savings comfortably overwhelm that premium. This is why most UK comparison sites suggest an EV tariff "starts to make sense" above roughly 6,000 to 7,000 miles a year. Your exact break-even depends on your peak rate and your charging discipline, which is what the widget below works out.

What you should actually do

An EV tariff is a contract, not an automatic saving. Estimate three numbers honestly before signing up, not after.

Estimate your annual charging kWh honestly

Take your annual mileage from your MOT history or odometer. Divide it by your EV's real-world efficiency, not the WLTP brochure figure. A Tesla Model 3 averages around 3.8 miles per kWh in a UK climate; a Volkswagen ID.3 sits closer to 3.5; a larger SUV like a Kia EV9 can drop to 2.8. Cold weather can knock another 20 to 30 percent off range in winter.

• 8,000 miles a year at 3.5 miles/kWh: around 2,286 kWh charged.
• 12,000 miles a year at 3.5 miles/kWh: around 3,429 kWh charged.
• 15,000 miles a year at 3.5 miles/kWh: around 4,286 kWh charged.

Decide on smart-controlled vs simple TOU

If you have a compatible smart charger (Ohme, Indra, Wallbox Quasar) or a vehicle the supplier can control (most modern Tesla, BMW, Volkswagen Group EVs), an intelligent tariff like Intelligent Octopus Go gives you a wider effective off-peak window and forgives the occasional out-of-hours plug-in. If you have a basic charger or a hybrid, a simple TOU tariff like a fixed 23:30 to 05:30 window is safer.

Either way, a smart meter (SMETS2) is mandatory. If you still have a SMETS1 meter or no smart meter at all, ask your current supplier to upgrade you. The upgrade is free, but waiting times in some regions still run to several months.

Conclusion: a tariff is a contract, not a savings guarantee

The 7p off-peak rate is real. It is also only part of the picture. An EV tariff saves you money when your mileage is high enough, your charging is disciplined enough, and your peak-rate household use is small enough to absorb the premium the supplier charges in exchange for the cheap window.

Use the calculator above, plug in your honest mileage and your real off-peak share, and read the verdict. If you cannot shift at least 70 percent of charging into the cheap window, the cap is usually the safer home for your bill, and you can revisit when your habits or your annual mileage change.