Free electricity calculator
Electricity Bill Change Explainer
Compare daily electricity use, daily bill cost, and effective cost per kWh across two bills. The result is arithmetic—not a diagnosis.
Why compare per day?
Two bills can cover different numbers of days. Dividing usage and cost by inclusive billing days makes the comparison more transparent. It still does not adjust for weather, occupancy, thermostat choices, or equipment behavior.
Effective cost per kWh means total bill amount divided by recorded kWh. It can include fixed fees, taxes, riders, and other charges; it is not necessarily your utility's tariff rate.
A bill-length example
An earlier 28-day bill with 840 kWh is 30 kWh per day. A later 33-day bill with 924 kWh is 28 kWh per day. Although the later bill contains 84 more kWh, daily use is about 6.7% lower. That arithmetic does not explain the cause.
| Period | Days | Usage | Usage per day |
|---|---|---|---|
| Earlier | 28 | 840 kWh | 30 kWh |
| Later | 33 | 924 kWh | 28 kWh |
Calculator unavailable
Temporarily unavailable. We’re working to restore this tool. No information has been collected.
The worked example above remains available without sending any bill values.
Keep the limits in view
A change in daily use or cost does not prove that an appliance is failing, the bill is wrong, or the home is inefficient. Review the bill details and seek the appropriate utility or qualified professional when the underlying record needs clarification.
Your entries are used only for this calculation. They are not saved to your account, placed in the page URL, or included in analytics.