How to calculate an electricity bill
Start with the billed period, not the payment date. Find the meter readings and the kWh charged. A payment can include a previous balance, so it is not always the cost of this period’s electricity.
Read the fields in order
Confirm the service address and meter identifier, then the opening and closing readings and their dates. Apply any stated multiplier before comparing their difference with billed kWh. Next check energy, delivery, fixed fees, adjustments and tax. Finally reconcile current charges with prior balances and payments. A per-kWh delivery charge can join the variable rate only when it applies to the same quantity. A fixed delivery fee belongs separately.
Rebuild the current-period charge
For a flat energy rate, multiply kWh by the price per kWh. Add the fixed service fee, then apply tax only to the charges that your provider taxes. For an illustrative USD bill with 280 kWh at USD 0.24/kWh and a USD 12 service fee, the pretax total is 79.20. If all charges attract 5% tax, the result is 83.16.
Charges outside the model
Check whether fuel adjustments, credits and minimum charges appear separately. Our calculator taxes the full subtotal including the service fee; if your tariff uses a different tax base, calculate that tax separately rather than forcing the bill into the model.
Keep the tariff with the bill
Keep the bill’s tariff page with your monthly record. Compare estimated charges with the current-period charge, and investigate any difference before changing your household routine.
Electricity & Water Bill Calculator
Worked example: Recalculate service charges and tax
Related reading: How time-of-use electricity pricing changes your costs
Reference: EIA: electricity prices and time-based pricing.