Have a look at NoExhaust https://noexhaust.co.uk/electric/rangevrecharge/ to see current electric cars, vans and some motorcycles to see how electric pence per mile varies mainly according to the weight of the vehicle, though power and aerodynamics will also contribute.
The webtool links to full vehicle details and is suitable for any website in the car charging industry, large or small. The first client to add an electric car version it to their website is Anglia Car Charging based in Norfolk. https://angliacarcharging.comcar.co.uk/electric/rangevrecharge/