Price per Mile = No. of Miles per kWh × Price per kWh 

In most scenarios you’ll see the efficiency noted as the energy consumed (watt hours) per mile (wh/mi). To convert this to mi/kwh use: 1,000 divided by mi/kWh 

Cost to fill the battery

If you want to know how much it costs to fill the battery, then you’d want to use the below formula

Cost = Price per kWh × Battery Size ÷ 100

Cost of home charging

The most efficient and reliable way to charge your electric vehicle is to charge at home using a 7kw home charger. 

The cost would be included as part of your home energy bills and would depend on your tariff. 

Many energy providers offer special tariffs for EV drivers such as off-peak variable rates, which allow you to charge at a lower rate overnight. 

Using Ofgem’s energy price cap of 34p per kWh, the cost of charging the popular Cupra Born, Mini Electric and Volkswagen ID 4 are below.

Cost of charging your electric car at Tesco and major supermarkets

Many major supermarkets such as Tesco now offer several electric vehicle charging points for you to make use of while you shop. 

As of November 1, Tesco offers a number of charging speeds at the following prices, with the first 15 minutes of charging being free. 

• 7kw fast charger: 28p per kWh
• 22kw rapid charger: 40p per kWh
• 50kw Ultra rapid charger: 50p per kWh

If you have a home charger installed, using the 7kw charger at Tesco is a good way to top up at a reasonable rate when you’re away from home. Given that it would take 3-4 hours to fill the battery completely, it wouldn’t be advisable to rely on 7kw chargers at supermarkets as your sole method of charging.

If you wanted to completely replenish your battery, then the 22kw and 50kw rapid chargers would be able to do this in around 30 minutes.

Here are our example cars again, with the costs of charging them at Tesco.

NB. Rapid chargers will stop charging your vehicle at 80% to help save battery life, however we’ve used the cost to fill the battery to 100% as a comparison.

Rapid charging costs

As well as supermarkets, you can find rapid chargers at service stations along the motorway, which are useful for longer journeys. These are a little more expensive, with the average price now at 63p per kWh.

Can you charge your car for free?

Yes – the number of free public charging stations is growing around the UK. You can find free charging stations in many public car parks, attractions and hotels – again, very useful to use for topping up when away from home.

There are normally some restrictions, so be sure to check the specific charging station’s rules before making use of them.

Tips for reducing running costs

Here are some more tips on reducing your electric charging costs:  

• Keep an eye on any EV tariffs. Some energy companies offered special tariffs to electric car drivers which would allow you to charge at a cheaper rate overnight – when demand for the national energy grid is lower.
• Installing solar panels and storage batteries in your home would allow you to use any excess energy your home doesn’t use to charge your vehicle.
• Ask if your work offers a free charging point for employees, or if they might consider it as a benefit. It would incentivise staff to get to work early and grab the spots!
• Only charge your car to 80% – obviously, don’t do this if you are planning to go on a long journey, but generally keeping your charge at 80% or below will help maintain your battery longer term.

How electric car charging costs compare to diesel and petrol

With pretty much any model, it will be cheaper to charge your electric car at home than it is to fill up a diesel or petrol car at a petrol station. For example, the e-Golf costs 4p per mile compared to 14p per mile for the petrol equivalent model.

As we’ve seen recently petrol and diesel prices are subject to change, but to compare on December 2022 prices, filling up a Ford Focus with a 55 litre tank is around £100 for diesel and £85 for petrol, so even a Tesla Model 3 at the most expensive charging option at Tesco would be cheaper to charge up.

It is nearly always cheaper to fully charge your car at home. Petrol and diesel prices may change, and if you do frequently use Rapid or Ultra Rapid chargers in public/commercial car parks you could run the risk of spending a similar amount of money to a less sustainable petrol or diesel vehicle.