Electricity Cost Calculator
Estimate the running cost of appliances from wattage, usage time, quantity, and your own electricity rate. The calculation stays in your browser.
Formula
watts x hours x days / 1000 x rate
Appliance details
Quick presets
How to read the result
The calculator converts appliance wattage into kilowatt-hours, then multiplies that energy use by your price per kWh. Use the rate shown on your electricity bill for the closest estimate.
Compare appliances
Try the same usage period with different wattage values to compare heaters, air conditioners, lighting, laptops, or standby devices before changing habits.
Privacy-focused
Inputs are calculated locally in the browser. No account is required, and the result does not depend on any external energy pricing API.
Frequently Asked Questions
What electricity rate should I enter?
Use the price per kWh from your bill. If your plan has time-of-use rates, run the calculator separately for each rate period and add the totals.
Why does wattage differ from real usage?
Many appliances cycle on and off or change power draw by mode. Use measured wattage from a smart plug when you need a tighter estimate.
Can I calculate monthly cost?
Yes. Set the period to 30 or 31 days. The annualized figure uses your average daily cost multiplied by 365.