Appliance energy and standby use

Electricity Cost Calculator

Estimate what an appliance costs to run. Choose an editable example or enter your own wattage, operating hours and electricity rate.

Appliance and usage

Standby applies only to the remaining 24 minus active hours on each modeled day. Enter 0 W when unplugged or truly off. Days excluded from the model contribute no energy; if an appliance stays plugged in on those days, include them and average its active hours across all included days.

The annual estimate either repeats your modeled month 12 times or applies the daily pattern to 365 days. For example, 30 days per month repeated 12 times means 360 modeled days. A 31-day model repeated 12 times means 372; choose 365 days for a calendar-year approximation.

The starting $0.18/kWh rate is an example, not a current local rate. Use your utility's applicable energy rate. All presets are illustrative and remain editable; changing wattage, hours or standby switches the selection to Custom without overwriting your values.

Inputs stay in your browser and are not saved.

How electricity consumption is calculated

One kilowatt-hour is 1,000 watts used for one hour. Daily kWh = number of units × [active watts × active hours + standby watts × (24 − active hours)] / 1,000. Multiply by the modeled days to find monthly or annual consumption, then multiply unrounded kWh by the electricity price. Costs round to the nearest cent independently; annual cost may differ slightly from 12 times the displayed rounded monthly cost.

Choosing wattage and operating hours

Use measured wall power or the appliance's actual input rating. A rated maximum or a computer power supply's capacity is not necessarily its normal draw. For refrigerators, air conditioners and water heaters that cycle, enter equivalent hours running at the chosen wattage, not every hour plugged in. Do not add the same cycling or heat-loss energy again as standby. The presets are examples for exploring the calculation, not specifications for your device.

Presets include an air conditioner, space heater, refrigerator, washer, electric dryer, electric vehicle charger, gaming PC, pool pump and electric water heater. Each includes an editable power, time and standby assumption plus a device-specific note. Gas or fuel energy is not included.

Source reviewed October 5, 2026: U.S. Department of Energy: estimating appliance and home electronic energy use. Check an EnergyGuide label or metered usage for a more device-specific estimate.

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