Electricity use and cost estimate

Estimate energy use and cost from a device’s wattage, daily hours, period, and the kWh rate you enter.

Currency

Choose a display currency. No conversion or local tariff lookup is performed.

Rated power (W)

Enter the W value from the product label. Zero is valid; leaving it blank is an error.

Number of identical devices

Enter a whole number from 1 to 1,000.

Hours used per day

Enter 0 to 24 hours, up to three decimal places.

Period (days)

Enter a whole number from 1 to 366. The result shows the period.

Energy rate (currency/kWh)

Enter the kWh rate you have. Precision is limited to the selected currency’s minor unit.

Inputs are calculated in this browser only and are not stored or sent to a server. Only the currency choice may be saved here.

Result

Enter the values and select Estimate use and cost.

Getting started

Enter the device label’s wattage, the count of identical devices, hours used per day, number of days, and your electricity rate. The result shows total kWh and an energy-cost estimate using that rate.

Rules and limits

Energy (kWh) = watts × device count × hours per day × days ÷ 1,000. Estimated energy cost = energy × the kWh rate you enter.

Assumes constant use at the entered rated power. It excludes changing loads, standby power, time-of-use or tiered pricing, fixed charges, taxes, demand charges, and provider-specific terms. One kWh is 1,000 Wh.

Sources consulted