Electricity Cost Calculator
Find out what any appliance really costs to run from its wattage, daily run time, and your kWh rate — broken out by day, month, and year. See which devices quietly pad your power bill before you decide what to unplug or replace.
How to Use
- Enter the appliance wattage — check the label, nameplate, or a plug-in power meter.
- Enter how many hours per day the device actually runs (not just how long it is plugged in).
- Set the days per month it operates, usually 30 for everyday devices.
- Enter your electricity rate in dollars per kWh from your utility bill (the US average is about 15 cents).
- Read the daily, monthly, and yearly cost plus the energy used, and check the step-by-step Show Work below.
Show Work
Reference
About the Electricity Cost Calculator
Electricity Cost Calculator is a quick, free tool for building, materials estimation and site work. It works in your browser and keeps everything on your device. Find out what any appliance really costs to run from its wattage, daily run time, and your kWh rate — broken out by day, month, and year. See which devices quietly pad your power bill before you decide what to unplug or replace.
How it works
Enter your figures and the result appears instantly, updating the moment you change anything. There is no submit button and nothing to wait for, so it is easy to try a few what-if numbers and compare the results. Just check each box holds the kind of value it expects.
Want the deeper story? The Knowledge Base explains the ideas behind the tools in more detail.
Frequently Asked Questions
How do I find an appliance’s wattage?
Look for the nameplate or sticker, usually on the back or bottom, which lists watts directly or gives volts and amps (watts = volts × amps). For an exact reading, a cheap plug-in power meter shows real draw, which matters because many devices use less than their rated maximum. The tool uses whatever wattage you enter.
What is a kWh and how is the cost figured?
A kilowatt-hour is 1,000 watts running for one hour — the unit your utility bills you in. The tool multiplies watts by hours, divides by 1,000 to get kWh, then multiplies by your rate. A 1,500 W space heater running 4 hours a day uses 6 kWh, which at 15 cents is about 90 cents a day, or roughly $27 a month.
Where do I find my electricity rate?
It is on your utility bill, listed as a price per kilowatt-hour. Watch out, though: your true cost can be higher than the headline rate once delivery charges, taxes, and tiered or time-of-use pricing are added in. For an honest estimate, divide your total bill by the kWh used that month and enter that effective rate.
Why does my fridge cost more than its watts suggest?
A refrigerator’s compressor cycles on and off rather than running constantly, but it runs around the clock all year, so the hours add up. Enter the average hours the compressor actually runs per day, not 24. Always-on devices like fridges, modems, and standby electronics are exactly where small wattages turn into a real annual cost.
What is phantom or standby power?
Many devices draw a few watts even when off — TVs, chargers, game consoles, and anything with a remote or clock. Individually it is tiny, but across a house it can add up to a noticeable chunk of the bill. Plug a suspect device into a power meter, enter that standby wattage, and run the hours at 24 to see the yearly cost.
How do I use the Electricity Cost Calculator?
Just type your numbers. The answer shows up right away — there is no button to press. Change anything and it updates by itself.
Does it cost anything or need an account?
No. The tool is completely free, there is no account to create, and it keeps working offline after the page first loads.
Is anything I type uploaded?
No. The tool works entirely on your device, so the values you enter never leave your browser.
Common Use Cases
Pricing a single appliance
See what a space heater, dryer, or AC actually adds to your bill so you can decide whether to run it less.
Comparing old vs. new equipment
Plug in the wattage of an old appliance and an energy-efficient replacement to see how fast the savings pay back the upgrade.
Hunting down bill spikes
Test the always-on and high-draw devices in your home to find what is quietly driving up the monthly cost.
Sizing a generator or solar offset
Total up appliance energy use to understand the daily kWh you would need to back up or generate.
Estimating a shop tool or grow setup
Calculate the running cost of high-wattage equipment that operates for set hours a day.
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