How this calculator works
Build a monthly household electricity estimate by combining HVAC, water heating, appliances, lighting, EV charging, and other loads.
Start with categories you can verify
Whole-home consumption is the sum of many loads. Utility interval data, appliance meters, circuit monitoring, EnergyGuide labels, and the calculators on this site can provide better category inputs than guesses.
Separate seasonal and continuous use
HVAC can dominate in the hottest or coldest months, while refrigeration, networking, pumps, and standby equipment form a steadier base load. Build more than one scenario when seasons differ substantially.
Reconcile the model with the bill
If the category total is far below the billed kWh, investigate unmodeled electric heating, water heating, pumps, dehumidification, EV charging, longer billing periods, or equipment faults. The utility meter remains the authoritative whole-home total.
Frequently asked questions
Should fixed charges be included in the electricity price?
Use either an all-in price without a separate fixed-fee input, or a variable energy price plus the fixed monthly charge. Do not count the same fee twice.
Why does my estimate differ from the bill?
Runtime, cycling, weather, unlisted loads, billing-period length, rate tiers, taxes, and estimation errors can all contribute.
Can this predict next month exactly?
No. It is a category model for planning and diagnosis, not a utility bill forecast or guarantee.
Use equipment documentation, your utility rate schedule, and measured data when they are available.