Free Electricity Cost Calculator
Estimate the daily, monthly and yearly electricity cost of running a device.
What is the Electricity Cost Calculator?
Estimate the daily, monthly and yearly electricity cost of running a device.
Power in watts divided by 1,000 gives kilowatts, multiplied by hours per day and device count for daily kWh. That is multiplied by your price per kWh, and scaled to 30.4375 days a month and 365 days a year.
Quick, reliable engineering arithmetic saves time on site and in the workshop. These tools show their working so you can check the result.
How to use the Electricity Cost Calculator
Using the electricity cost calculator takes a minute or two. Your entries are saved in this browser, so you can come back later and carry on.
Step 1
Enter your values, choosing the units you are working in.
Step 2
Read the result and the supporting numbers shown beneath it.
Step 3
Check the result against a second method or a reference table before you rely on it.
Tips for better results
Find your rate on your bill, which may include delivery charges or tiered pricing. Devices that cycle, such as fridges, use less than their rated power.
Keep units consistent from start to finish.
These tools are for estimates. Safety critical designs need a qualified engineer.
Privacy and where your data goes
Everything you type into the electricity cost calculator stays on your own device. Zapxa does not receive your numbers or documents. If you clear your browser data, your saved entries will be removed, so download a PDF of anything you want to keep.
Frequently asked questions
How do I find a device's wattage?
Look on its label or manual, or use a plug-in energy meter. Amps times volts also gives watts.
Why is monthly cost based on 30.4 days?
It is 365 divided by 12, the average month length, so the monthly figure is one twelfth of the yearly cost.
Is the electricity cost calculator free?
Yes. It is free to use with no signup, no watermark and no usage limits.
Is my data private?
Yes. Your inputs are processed in your browser and saved only in its local storage. They are not uploaded to our servers.
Does it work on mobile?
Yes. Zapxa works on phones, tablets and desktops. Use the print button or download a PDF to keep a copy.
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