Where do I find the wattage of my appliance?

Check the label on the back or bottom of the device, the product manual, or the manufacturer's website. The wattage is usually printed near the power input specifications (e.g., "120V ~ 60Hz 1200W").

What is a typical electricity rate per kWh?

Rates vary widely by country and utility provider. In the US, the average is around $0.13–$0.17 per kWh. In Europe it ranges from €0.10 to €0.40. Check your latest utility bill for your exact rate.

How is the monthly cost calculated?

Monthly cost assumes 30 days of use at the specified daily hours. The formula is: (Watts / 1000) × Hours/day × 30 × Rate/kWh. Yearly cost uses 365 days.

Can I calculate cost for multiple appliances?

Yes — run the calculator separately for each appliance and add the results together. For a household audit, focus on high-wattage devices like air conditioners (1000–3500W), water heaters (3000–4500W), and electric ovens (2000–5000W).

What if my appliance does not run at full wattage the whole time?

For cycling appliances like refrigerators, use the duty cycle. If a 200W fridge compressor runs about 50% of the time, enter 100W as the effective wattage, or reduce the hours accordingly.

kWh Cost Calculator

Name: kWh Cost Calculator
Availability: InStock
Author: Nham Vu

Enter appliance wattage, daily usage hours, and your electricity rate to instantly see daily, monthly, and yearly running costs.

Appliance & Usage Details

Appliance Wattage

Found on the device label or spec sheet.

Hours Used Per Day

hrs/day

Average hours the appliance runs each day.

Electricity Rate

$ / kWh

Check your latest electricity bill for this figure.

Currency Symbol

Common Appliance Wattages

LED Bulb8–15 W

Laptop30–70 W

Desktop PC200–400 W

Refrigerator100–400 W

Washing Machine500–1200 W

Electric Kettle1200–3000 W

Air Conditioner1000–3500 W

Electric Water Heater3000–5500 W

Click a row to pre-fill the wattage field.

Fill in the details on the left and click Calculate Cost to see your results.

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Summary

Enter appliance wattage, daily usage hours, and your electricity rate to instantly see daily, monthly, and yearly running costs.

How it works

Enter the appliance wattage in watts (W) — found on the device label or spec sheet.
Enter how many hours per day the appliance is typically running.
Enter your electricity rate in cost per kilowatt-hour (kWh) from your utility bill.
The calculator converts watts to kilowatts, multiplies by daily hours to get daily kWh consumption.
Daily kWh is multiplied by your rate to produce a daily cost, then scaled to monthly (30 days) and yearly (365 days) figures.

Use cases

Estimate the running cost of air conditioners, heaters, and refrigerators.
Compare energy costs before buying a new appliance.
Identify high-consumption devices that are inflating your electricity bill.
Calculate potential savings from switching to a more energy-efficient model.
Budget monthly electricity costs for a home office or workshop.
Determine payback period for energy-saving upgrades.
Audit energy usage across multiple devices in a facility.
Educate students about power, energy, and cost relationships.

Frequently Asked Questions

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Last updated: 2026-05-23 · Reviewed by Nham Vu