Home Energy Cost Estimator
Estimate your monthly electric bill by appliance from your kWh rate and hours-per-day usage.
See which devices are quietly costing you the most.
The old version of this page asked you to enter the percentage of your bill that each appliance uses. That was the wrong question. If you knew the percentages already, you would not need a calculator. So this page now does the actual work: take typical wattages, multiply by the hours you run each device per day, multiply by your electricity rate, and add it all up.
The math is one line for every appliance:
monthly cost = (watts × hours_per_day × 30) / 1000 × price_per_kWh
Watts come from the appliance label or, for big shared loads like central A/C, from a sensible average. The calculator ships with defaults pulled from US Department of Energy and EnergyStar reference tables, so you can leave a row alone if you have no idea what the wattage is.
A quick reality check on the rate. The US national average residential price is around 16 cents per kWh as of early 2026, but it ranges from 11 cents in Louisiana and Idaho to over 30 cents in California, Hawaii, and most of New England. European rates are usually higher — Germany sits near 35 cents per kWh after recent energy shocks, the UK around 27 pence, France about 22 cents. Check your last bill for the real number.
The big surprises in most homes are not the devices people worry about. People panic about leaving a phone charger plugged in (about $1 per year) and ignore the 1500 W space heater that ran for six hours a night last December (about $43 for the month at 16 cents). Heating, cooling, and water heating dominate every honest energy audit. Lighting and electronics are almost always small.
Two things this calculator does not try to do. It does not estimate gas or oil costs — fuel-fired heat and water heating are a different math. And it does not model time-of-use rates, demand charges, or solar net metering. Plug in a single average rate, run the numbers, and you will see exactly which appliances drive your bill. If you want to attack one of them, that is a real plan, not just an averaged-out percentage.