Home charging calculator guide

Below are some details on how to use the Home Charging Calculator and the assumptions made when calculating your home charging time and cost.

Selecting your vehicle

On the first screen you need to select your vehicle – both pure electric vehicles and plug-in hybrids are included on the list. The default shows you new cars that are available to buy now, but you can also select the Used button to find any plug-in car which has been on sale in the UK. Once the vehicle has been selected you can look at the vehicle details.

Adding your home charging details

On the input screen you are asked to provide details about your home charging point – in particular, whether it is a 3kW or 7 kW rated unit. If you’re not sure which to select, most standard units are 3 kW. If you select 7 kW you will be prompted to confirm whether you vehicle is capable of charging at 7 kW – only some vehicles come with the necessary on-board charging.

The home electricity cost defaults to the UK average. Source: UK Government – updated annually. You can edit and change to your own tariff if you wish. The estimated real-world range for your selected vehicle is shown, if you, experience a different real-world range based on your driving patterns, you can enter your own figure if you wish.

The calculator will work out your home charging time and cost using the connector speed, average UK electricity price, the battery capacity and the estimated real-world range.

Your home charging results

Your charging time and cost for your vehicle are calculated using the data selected. As most people don’t use up all their battery charge in one go, you very the inputs to select the % charge you typically add to your battery.

A worked example is shown below for the Nissan LEAF Tekna 30 kWh using a 3 kW charger.


Nissan LEAF Tekna 30 kWh

Description Data
Electricity price (typical UK average) 34p/kWh
Manufacturer battery capacity (indicative)     30kWh
Official NEDC range 155 miles
Real-world range (estimated) 124 miles


Your charging time (hours)
Charging time (hours) = battery energy added (kWh) ÷ charger power (kW)
Example: 80% charge a Nissan LEAF 30kWh with a 3kW charging point
(30kWh * 80% ) ÷ 3kW = 8 hours

Your charge cost (£)
Charge cost (£) = battery energy added (kWh) x electricity cost (p/kWh)
Example: 80% charge a Nissan LEAF 30kWh
30kWh * 80% * 34p/kWh = £8.16

kWh added
Battery energy added (kWh) = charger power (kW) x time (hours)
Example: 80% charge a Nissan LEAF 30kWh
3kW * 8 hours = 24kWh

Cost per mile (p/mile)
Cost per mile (p/mile) = Charge cost ÷ miles added
Example: 80% charge a Nissan LEAF 30kWh
£8.16 ÷ 124 miles = 6.6p



All results are based upon the theoretical optimum operating efficiency of the vehicle as quoted by the manufacturer. Please bear in mind that you may achieve very different results in real life. These tools should be used for comparative purposes only.

The cost per mile shown is for pure electric driving only. All calculations use independent data from Next Green Car, based upon the manufacturer’s quoted indicative battery size (kWh), the home charger power (kW), the estimated real-world electric range figure and the price of electricity.

You can change the range figure and electricity price to more closely reflect your experience. The real-world range figures are based on real-world driving tests or where this data is not available, estimated from official NEDC or WLTP figures (depending on model), which are obtained from the official EU test data. These figures are intended for comparisons between vehicles and may not reflect real driving results.

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