How energy cost is estimated
Electricity running cost is usually estimated as watts divided by 1,000, multiplied by hours used, then multiplied by the unit rate per kWh.
Whole-bill estimates also include standing charges, VAT, billing period, gas usage, and seasonal usage changes.
Why your real bill may differ
Tariffs, standing charges, regional pricing, payment method, meter type, appliance cycles, thermostat settings, and household behaviour can all change the actual cost.
Use editable assumptions
Energy prices change. Treat any example rate as illustrative and enter the unit rate from your current bill or tariff for a better estimate.