Appliance Energy Cost Calculator

Estimating appliance energy use

Start with input power from the appliance label. Add typical active hours and days used each month rather than assuming continuous operation.

Formula and methodology

Daily consumption is power in kW × hours. Monthly consumption multiplies it by active days, and annual consumption assumes twelve matching months. Each cost is the corresponding kWh value times the USD rate.

Worked example

A 900 W appliance used 2.5 hours on 20 days monthly consumes 2.25 kWh per active day, 45 kWh monthly, and 540 kWh annually. At $0.17 per kWh, cost is $7.65 monthly and $91.80 annually.

Assumptions and limitations

This steady-power model excludes start-up surges, standby use, duty cycles, efficiency changes, time-of-use tariffs, taxes, and fixed charges. Use a plug-in meter when demand varies substantially.