Your EV usage
Current flat tariff
EV tariff
Preset rates are approximate and updated periodically. Always verify with your supplier.
Enter your usage and tariff details above
This calculator compares what you'd spend on EV charging under a standard flat-rate tariff versus a dedicated EV tariff with cheaper overnight rates, using your car's max range and battery size to work out real-world consumption.
Your car's efficiency (miles per kWh) is derived from its advertised max range divided by its battery size, then applied to your monthly or annual mileage to estimate how much you charge each month. EV tariffs typically charge more per unit during the day, so the saving depends on how much of your charging you can shift to the cheaper overnight window — this tool assumes all EV charging happens off-peak, since that's the whole point of switching. If your household uses a lot of daytime electricity for other things, factor that in separately; this tool focuses on the car charging cost only.
Where a flat tariff has a lower standing charge than an EV tariff, low-mileage drivers can sometimes come out ahead staying on the flat tariff even though its unit rate is higher — the break-even figure shows the monthly mileage above which the EV tariff wins.
Both are optional. Including a charger installation cost spreads it evenly over the number of months you choose and adds it to both tariffs' annual totals, so it doesn't change which tariff wins but does affect the absolute figures. The petrol/diesel comparison estimates what the same mileage would cost on fossil fuel, for a full three-way comparison.
Preset tariff rates are approximate and updated periodically — always confirm current rates with your own supplier before switching. This tool doesn't account for seasonal efficiency changes, home solar/battery storage, or off-peak windows that don't align with your actual charging habits.