EV tariff calculator: Your estimated savings revealed

What is an EV tariff
and how much money can I save?

Working with any make of EV and with any home charger, the British Gas EV tariff keeps costs down, saving the average EV driver in the UK an estimated £332 a year¹ versus a Standard Variable tariff set to Ofgem’s current price cap rate.

EV tariffs are different to our regular energy tariffs because they offer a discounted rate during off-peak electricity hours of 7.9 pence per kWh between 12am – 5am. This allows you to charge your EV and even use other domestic appliances at this reduced cost.

Plus, during peak daytime hours, we keep your tariff as close to your normal electricity rates as possible.

EV energy tariffs might not offer the best value if your driving patterns mean you don’t charge much at home or need to regularly charge your car during peak hours. The way you use electricity more widely at home also affects whether an EV tariff will be cheaper overall. But, for most people, there are not many disadvantages to switching to an EV tariff.

Try out the EV tariff savings calculator below to gain a personalised estimate of how much you can save per charge as well as annually.

The EV tariff savings calculator

How to use the savings calculator

To estimate what you could save, simply input your car model, expected annual mileage and how much you're currently paying for your electricity (if you're not sure we can compare costs to a Standard Variable tariff at current Ofgem price cap rates). You’ll be able to see just how much you can save per charge and annually in comparison to your current tariff.

Compare EV charging costs

We'll also compare your estimated EV charging costs with our EV tariff and the cost of charging at public chargers, potentially saving you up to thousands each year. And, for those conscious of their environmental footprint, or thinking of making the move to an electric car, you’ll also find out the estimated reduction in your direct driving emissions in an electric car versus a traditional petrol vehicle.

What’s the most you can
save with an EV tariff?

Not everyone’s savings will be the same – it all depends on the EV model you have, your driving habits and what you’re paying for your electricity.

Our calculations suggest the average driver on a Standard Variable tariff linked to Ofgem’s price cap rate can save an estimated £7.08² on each charge, and up to £332¹ annually by switching to the British Gas EV tariff.

These savings could go up even further when you look at the differences between our EV tariff and both slow/fast and rapid/ultra-rapid public chargers. The average driver could be saving an estimated £20.52 per charge and £961 annually versus slow/fast public chargers. Looking at rapid/ultra-rapid public chargers, there’s also an estimated saving of £30.76 per charge and £1,441 annually.⁶

To calculate estimated savings per charge, we combined the kWh required to fully charge your battery (considering going from 20% to 80% as a full charge) and worked out the estimated cost for this energy using the British Gas EV tariff rate. Next, these costs are compared against your current standard tariff rate, as well as average public charging rates across the country. To calculate annual savings, we take your annual mileage, and the corresponding yearly kWh required (using the battery efficiency of your vehicle) to find the estimated costs of this energy across the different charging options and rates.

How can an EV tariff reduce
your carbon footprint?

Not only can you save more money when switching to an EV tariff, but the chances are you’ll be saving on your environmental footprint too if you’re driving an electric car instead of a petrol one.

With EVs already producing zero tailpipe emissions, an EV tariff could further boost your sustainability. By switching to a tariff suitable for off-peak electricity, it’s more likely you’ll be using energy generated from renewable sources. During peak hours, utilities rely on older, more polluting power plants, increasing greenhouse gas emissions. So, shifting electricity use to off-peak hours reduces the need for fossil fuels and aligns with renewable energy generation, even if you’re making smaller changes.

Our calculations show the average UK driver can save an estimated 2,287kg of CO₂ annually by driving an EV³ compared to an internal combustion engine (ICE) vehicle. That’s the equivalent of burning around 1,143kg of coal, or around 972 litres of petrol.⁴

Although your carbon emissions are reduced with a hybrid car – and lowered even further with a completely electric vehicle – there will be some indirect emissions from producing the electricity needed for charging.

Save even more with our EV tariff

Our two-rate tariff means lower electricity prices between the off-peak hours of 12am – 5am⁵ whilst on-peak hours are close to normal electricity rates in the daytime.

With our EV tariff, you can save even more from a range of benefits.

“We’ve made is easy for you to see how much you could save on charging with an EV tariff. Compared to a standard tariff, or public charging (if you’re considering a home charger), a switch could save you hundreds or Even thousands.”⁶

“Make sure to look at tariffs that have the option of on-peak and off-peak hours, so that you can use low times to make the most of your energy. If you’re choosing to charge your car at night (which saves your bills in the long run) you’ll see a significant improvement in the affordability of your driving.”

Paul Lodwidge, Head of Energy Product & Propositions, British Gas

How did we calculate your financial savings when switching to our EV tariff?

Using the off-peak British Gas EV electricity rate (7.9p per kWh), we calculate how much it would cost you to charge your specific electric vehicle per charge and year with British Gas. Calculations are based on yearly miles driven inputted, as well as the battery size and battery efficiency (kW/ mile) of the vehicle (source: ev-database.org).

We take the British Gas EV electricity rate calculations and compare this to the average energy price cap rate (24.5p per kWh) as well as the cost of slow/fast public chargers and ultra-fast/rapid chargers. 

• Average Ofgem energy price cap rate (source: ofgem.gov.uk) as of October 2024.
• Cost of slow/fast public chargers and ultra-fast rapid chargers (source: zap-map.com).

A full charge is considered charging from 20% to 80%, based on guidelines to maintain battery health.

How did we calculate the number of CO₂ emissions saved with an EV?

CO₂ emission savings were calculated by multiplying the number of average car miles with the number of CO₂ per mile, based on a typical medium petrol-powered car emitting 309g CO₂ per mile (source: 8billiontrees.com) and an average of 7,400 miles annually (source: britanniacarleasing.co.uk).

Data for this campaign is up-to-date as of September 2024.