It’s a really important question for EV owners: How much does it cost to charge an electric car?
If the answer to this question was “a lot of money”, then people wouldn’t buy electric cars.
Fortunately, the cost of charging an electric car is low. The exact cost depends on two factors:
- How long you need to charge for (or how many miles you drive per year), and
- How much you pay per unit (kWh) of electricity during the charging period.
Let’s get stuck in with some examples.
Charging costs – Summary
In the sections below, we explain in detail how to work out EV charging costs in any situation. First, however, we provide a quick overview.
The 2018 Nissan Leaf, with a 40 kWh battery, is a popular all-electric car on Britain’s roads.
The annual cost of charging the Leaf depends on (i) how many miles you drive per year and (ii) how much you pay per unit of electricity (kWh) when you are charging it.
The best and most likely scenario for most electric car owners is to charge at home during the night on a cheap, off-peak tariff, say 7p per kWh.
Charging at home during the day will typically cost you about 14p per kWh.
If you charge when out and about, perhaps at motorway charging stations, the cost could be about 30p per kWh.
Here is a table showing the total annual costs for charging an average EV, like the Nissan Leaf, for five different annual mileages. If you have solar panels on your home, you can get these costs down even further.
Below are further examples showing how to calculate daily EV charging costs in various situations.
We also show what effect having solar panels and battery storage has on your charging costs. If you’re clever with when and how you charge your electric car, you can enjoy very low annual running costs indeed.
The Cost to Charge an Electric Car at Home
The Renault Zoe is one of the most popular EVs in the UK. The 2018 model has a 41 kWh battery.
Imagine you arrive back home after work at the end of the day and the battery is almost completely empty.
You plug the Zoe into your 7 kW home charging point and go in for well-earned cup of tea.
Home EV charging points are referred to in many different ways and you may also hear them called wall boxes, charging stations, and EVSE (Electric Vehicle Supply Equipment).
Let’s assume you pay a flat rate for your electricity of 14p per unit (kWh).
In other words, whatever time of day it is, you always pay 14p if you consume 1 kWh of electricity.
As your Renault Zoe is more or less at 0% charge and you want to have it at 100% by the morning, you need to get 41 kWh into the battery.
41 kWh of electricity will cost you £5.74. Where did that figure come from? You multiply your electricity rate of 14p by the number of kWh you need – 41 kWh – and you get £5.74 (14p x 41).
This formula works for any electric vehicle. Just calculate how many kWh you need to put into your battery to reach 100% charge, and then multiply that number by the rate you pay for your electricity.
It will take about 6 hours of charging with a 7 kW charger to go from 0% to 100% charge on a Zoe. For an explanation of how to calculate charging times, please read our handy guide.
If you are getting confused by energy and electricity terminology, check out our Energy Terminology help page.
However, you may not have a flat rate for electricity consumption.
For example, if you are an Economy 7 customer, you will probably have both a peak rate of say 15p and also an off-peak rate of about 7p. How much does it cost to charge an electric car with Economy 7?
The off-peak rate typically runs from midnight until 7am. This is good news for EV owners. Charge your electric car after midnight and you will pay only 7p per unit.
Here’s the maths for the Renault Zoe with a 41 kWh battery on empty. 41 kWh into the car’s battery at 7p costs £2.87. Wow, that’s cheap!
And because it takes about 6 hours to charge a Zoe from 0% to 100% on a 7 kW home charger, you can fit those 6 hours into the 7 hour time slot between midnight and 7am. Bingo – lower bills.
Obviously you don’t want to be up at midnight plugging your car in at the stroke of 12. Cars conveniently have timers and you can program the car to start charging when you want it to.
Nowadays, there are many more tariffs on offer than simply a flat rate and Economy 7.
Many of these new electricity contracts are called ‘smart tariffs‘. You will often have more than two different tariff rates, depending on the time of day.
To be able to make use of a smart tariff, your electricity supplier will install a smart meter, free of charge. For more details about smart tariffs and smart meters, please read our Smart Meter Tariffs page.
How much does it cost to charge an electric car on a smart tariff?
To calculate how much it costs to charge your EV on a smart tariff, you carry out the same calculations as above.
The only thing you have to watch out for is if your electric vehicle charging period spans two different smart tariff rate periods.
Here’s an example. Your Renault Zoe needs to be charged for 6 hours to go from 0% to 100% charge using a 7 kW home charge point. Imagine you charge the car from 12:30am (middle of the night) until 6:30am in the morning.
With Octopus Go, a popular, low-cost, smart tariff for EV drivers, you are charged at:
- 5p per kWh from 12:30am to 4:30am (4-hour slot)
- About 14p per kWh (exact rate depends on where you live) from 4:30am to 12:30am (20-hour slot)
Remember: your 7 kW charger gives you 7 kWh in 1 hour.
- So, for the 4 hours of charging from 12:30am until 4:30am, the calculation is: 7 kWh x 4 hours x 5p = £1.40.
- For the 2 hours of charging from 4:30am to 6:30am, the calculation is: 7 kWh x 2 hours x 14p = £1.96.
So those 4 hours of charging at the very low rate of 5p per kWh costs less than 2 hours of charging at the higher rate of 14p per kWh.
The total cost of charging the car for those 6 hours, spanning two different rate periods, is therefore £3.36 (£1.40 plus £1.96).
Solar Panels and Battery Storage
Where it gets really interesting is with solar panels.
How much does it cost to charge an electric car with solar panels?
If you have a solar panel system on your roof, you can generate free electricity from the sun. That’s right – free. There’s no 5p, 7p, 8p, 11p, 14p, 15p, 18p rate to pay. Your rate with solar panels is 0p.
The question then is: how can I get that 0p rated solar electricity into my electric car? There are two ways:
- If your car is plugged into your home charging point and your solar panels are producing electricity, that solar electricity will flow into your car and charge your car’s battery.
- If you come home from work in your EV in December at 6pm and it’s pitch black, your solar panels won’t be able to charge your car. No sun = no solar electricity. But, if you have battery storage, you’re in luck. Home battery storage, such as the Tesla Powerwall, will capture your excess solar electricity generated during the day and then charge your car with it when the sun has gone down.
In both cases – either with solar panels only or solar panels plus battery storage – you can charge your car with free solar electricity.
It’s worth pointing out, however, that solar panels may well not be able to charge your electric car fully on their own. Car batteries can be very big.
Most EV owners therefore combine solar PV panels with low, off-peak, night-time rates in order to get the cost of electric motoring right down.
Cost to Charge your Electric Car with Solar Panels
Imagine it’s 1pm on Saturday in May.
The sun is shining and your solar panels are producing 3 kW of power (if you don’t know your kW from your kWh, read out terminology page).
Your EV is plugged into its 7 kW chargepoint on your garage wall. Let’s assume some electric devices in your house are turned on (lights, computers, fridge, freezer, etc.) and they are drawing 1 kW in total.
In this case, 1 kW of your 3 kW solar power will meet the needs of your home devices. That leaves 2 kW left over. That 2 kW will then go towards charging your electric car.
As your EV wall charging point is rated at 7 kW, it takes 2 kW from the solar panel system, but then needs an additional 5 kW. It takes that extra 5 kW from the national grid.
So, how much does it cost to charge your electric car in this case?
Let’s consider the period of time from 1pm to 2pm.
During that one hour slot, the 7 kW car charger will get 7 kWh into the car (7 kW x 1 hour = 7 kWh).
2 kW of the 7 kW of power is coming from the solar panels. As a percentage, that’s 29% (2 kW divided by 7 kW x 100).
29% of 7 kWh is 2 kWh. The solar electricity is costing you 0p. So those 2 kWh of solar electricity have cost you absolutely nothing.
The remaining 5 kWh needed from the national grid to charge the car from 1pm to 2pm will be charged at your agreed electricity rate. Let’s say the rate from 1pm to 2pm at weekend is 13p. The 5 kWh will therefore cost you 65p (5 kWh x 13p).
In summary, in the situation above, to charge your electric car for one hour on a Saturday afternoon will cost you 65p, if you have solar panels.
Cost to Charge your Electric Car with Solar Panels and Battery Storage
In the example above, if you had both solar panels and battery storage, instead of importing those 5 kWh from the grid, you could get them from battery storage.
How much does it cost to charge an electric car with solar panels and battery storage?
Your home battery would discharge 5 kWh into the car. How much would that cost? It depends on how the kWh got into the home battery in the first place.
If your home battery storage was charged by your solar panels, then those 5 kWh would cost nothing. That 1 hour charging of your car from 1pm to 2pm would cost 0p in total – 0p from the solar panels plus another 0p from the battery (containing free, stored solar electricity).
If, on the other hand, your battery storage had been charged by off-peak electricity costing say 7p per unit, then those 5 kWh would cost 35p (5 kWh x 5p).
The Cost to Charge an Electric Car Away from Home
If you are on road trip and have stopped to charge your EV at a motorway service station, it will cost you more to charge your car than at home.
This is because you will be charged more per unit (kWh) of electricity.
At home, you might pay 14p per kWh, but at a public charging station the cost is often around 30p per kWh.
As a rule of thumb, the cost is about double what you would pay at home, using the 14p home day rate.
But if you are used to charging your electric car at night on a cheap rate such as 7p, then public charging will typically cost more than four times what you pay at home.
If you have a Tesla Model 3, Model X or Model S, you will normally use Tesla’s own Supercharger network. Pricing varies depending on which Tesla car you have and when you bought it – see our dedicated Supercharger page for more information.