Power Consumption Calculator
Calculate electricity usage and cost per device.
Frequently Asked Questions
How is electricity cost calculated from watts? +
Multiply the device wattage by hours of use to get watt-hours, then divide by 1000 to get kilowatt-hours (kWh). Multiply kWh by your electricity rate to get the cost.
What is the average electricity rate in the US? +
As of 2024, the average US residential rate is about $0.16 per kWh. Rates vary significantly by state, from around $0.10 in some states to over $0.30 in Hawaii and parts of New England.
How do I find the wattage of my device? +
Check the label on the device or its power adapter. It usually lists watts (W) or amps and volts (multiply them to get watts). You can also use a plug-in power meter for exact readings.
Does a device use power when turned off? +
Many devices draw standby (phantom) power when plugged in but not in use. This is typically 1-5 watts per device. Over many devices, this can add up to 5-10% of household electricity use.