Where do I find a device's wattage?

Check the label or nameplate on the device itself, its manual, or the manufacturer's product page — it's often listed directly in watts, or as volts × amps.

Where do I find my electricity rate?

Your utility bill lists your rate per kWh, often called the 'energy charge' — note that some utilities also add other fees not captured by this simple estimate.

Electricity Cost Calculator

Estimate how much it costs to run an appliance or device, based on its wattage, how long you use it, and your electricity rate.

Power draw

watts

Hours used per day

Days used per month

Electricity rate

$/kWh

Cost Per Day

$0.08

Cost Per Month

$2.25

Cost Per Year

$27.00

How It Works

From watts to kilowatt-hours

Electricity is billed in kilowatt-hours (kWh). A device's energy use = watts ÷ 1000 × hours used, and cost = kWh used × your rate per kWh.

Example

A 100-watt device run 5 hours a day at $0.15 per kWh costs about $0.08 a day, $2.25 a month, and $27 a year.

Common Mistakes

Confusing watts with kilowatt-hours — watts measure power (rate of energy use), while kilowatt-hours measure actual energy consumed over time.
Using a device's maximum rated wattage instead of its typical running wattage, which overstates actual cost for devices that cycle on and off (like refrigerators or AC units).

Frequently Asked Questions

Where do I find a device's wattage?: Check the label or nameplate on the device itself, its manual, or the manufacturer's product page — it's often listed directly in watts, or as volts × amps.
Where do I find my electricity rate?: Your utility bill lists your rate per kWh, often called the 'energy charge' — note that some utilities also add other fees not captured by this simple estimate.