Fuel Savings: Switching From Petrol to Electric

Switching from petrol to electric can meaningfully cut your fuel costs, because charging at home costs less per mile than refuelling at a forecourt in most scenarios. The actual saving depends on your energy tariff, how much you drive, and where you charge. The direction of travel is clear for the vast majority of drivers: running on electricity is cheaper than running on petrol. To get the most from your EV, the right charging cable for your car is the first practical decision to get right.

How much cheaper is charging versus filling up with petrol?

There is no single answer that holds for everyone, because electricity and petrol prices move constantly and vary by supplier, tariff, and region. What is consistent is the underlying dynamic: electricity costs less per unit of energy than petrol at the pump in almost all current scenarios. The most accurate way to calculate your own saving is to take your actual home electricity rate (from your bill), your EV's real-world efficiency in miles per kWh, and compare that cost-per-mile to what you currently pay per mile in your petrol car. Check gov.uk and your energy supplier for current rates before running any calculation.

Does where you charge make a big difference?

Yes, significantly. Home charging is almost always the cheapest option, especially if you are on a time-of-use tariff that offers lower rates overnight. Workplace charging, where available for free or at a subsidised rate, can reduce costs further still. Public rapid chargers are faster and more convenient on long journeys, but they typically charge a higher rate per kWh, which can close the gap with petrol noticeably. Drivers who rely mainly on public charging will see smaller savings than those who do most charging at home overnight.

What is a time-of-use tariff and is it worth switching?

A time-of-use tariff charges different rates for electricity at different times of day, with lower rates typically available overnight (for example, between 11pm and 6am, though the exact hours vary by supplier). For EV owners who can schedule overnight charging, this is often the most cost-effective way to charge. Whether switching makes sense depends on your household's overall electricity usage pattern, not just your EV. Contact your energy supplier or use one of the comparison tools on Ofgem's website to model the impact on your full bill, not just the charging portion.

Is a worked example useful for planning?

A rough worked example can help frame your thinking, provided you replace every number with your own real figures. As an illustration only, using round numbers: if your EV travels 4 miles per kWh (illustrative), and you pay 10p per kWh overnight (illustrative), the cost per mile would be 2.5p. If your petrol car returns 40 miles per gallon (illustrative) and petrol costs 140p per litre (illustrative), the cost per mile is approximately 16p. These numbers are for illustration only. Replace them with your current tariff, your car's real-world efficiency, and today's pump prices before drawing any conclusions. Visit your energy supplier's website and a live fuel price tracker for current figures.

What other running costs change when you go electric?

Fuel is the biggest line item, but other costs shift too. Road tax for zero-emission cars has changed; check the current DVLA rates, as the rules updated in 2025. Servicing costs are generally lower because EVs have fewer moving parts: no oil changes, no exhaust system, and regenerative braking extends brake pad life. Insurance can be higher for some EVs, particularly newer or larger models, so it is worth shopping around before you switch. Tyres wear at a similar or sometimes faster rate than on a petrol car due to the additional weight and instant torque, so factor that into your cost comparison.

Do I need any special equipment at home to charge?

Most EVs come with a portable charging cable that plugs into a standard three-pin socket, often called a granny charger. This works, but it is slow, typically adding 8 to 10 miles of range per hour. A dedicated home charger, installed by an OZEV-approved installer, charges significantly faster and is safer for regular overnight use. You will also want to make sure you have the right cable for your specific car: Type 2 is the most common connector for home and public AC charging in the UK, but the socket on your car determines what you need. See our guide to Type 2 charging cables and portable EV chargers for more detail.

Frequently asked questions

Will I definitely save money by switching to electric?

For most drivers who can charge at home, the running cost per mile is lower in an electric car than in a petrol equivalent under current pricing conditions. The saving is not guaranteed for everyone: drivers who rely heavily on public rapid charging, or who are on a high standard electricity tariff, will see smaller benefits. Calculate your own numbers using real current rates rather than relying on averages.

How do I find out what my electricity costs per mile?

Divide your electricity rate (in pence per kWh, found on your bill) by your EV's real-world efficiency in miles per kWh. For example, if your car does 3.5 miles per kWh and you pay X pence per kWh, your cost per mile is X divided by 3.5. Use your actual bill rate, not a published average, as tariffs vary considerably between suppliers and regions.

Is public charging always more expensive than home charging?

Generally yes, particularly rapid and ultra-rapid chargers, which carry a premium for speed and convenience. Some destination chargers at hotels, supermarkets, or car parks are free or low cost, which can help balance out the occasional rapid charge on longer journeys. If you are calculating an annual cost, estimate the split between home and public charging based on your actual habits.

Does battery degradation affect the fuel saving over time?

Battery capacity does reduce gradually over years of use, which means the car's real-world range shortens slightly. This does not significantly change the cost per mile from charging, because a less efficient battery uses a similar amount of energy for the same journey. It affects range and convenience more than running cost. Modern EV batteries are designed to retain most of their capacity over many years of normal use.

Are there any government incentives that affect the calculation?

The Plug-in Car Grant was closed to new applications, but other support exists. The OZEV home charger grant (currently the Electric Vehicle Homecharge Scheme for eligible properties) can reduce the upfront cost of a home charger installation. Check gov.uk for the current eligibility criteria and grant amounts, as these schemes are updated periodically and the available funding changes.

What is the best way to maximise my fuel savings as an EV driver?

Prioritise home charging on the lowest-rate overnight period your tariff offers. Avoid relying on rapid chargers for routine charging. Drive smoothly and use regenerative braking where possible. Keep tyres inflated to the recommended pressure. Plan longer journeys to use free or cheaper destination chargers where available rather than paying rapid charge rates throughout.

Getting the charging setup right makes a real difference to how much you save. Whether you are choosing between home charging options or need a cable for charging on the go, our guides to EV charging cables by car and portable EV chargers cover the practical decisions most drivers face after switching. You can also browse all our EV guides at the Guides index for more on running costs, range, and getting the best from your electric car.