WattWiseHow it works
A clearer picture of your power bill

Know what each appliance costs to run.

Enter watts, or fill in voltage and current separately. WattWise works out the estimated power and shows your costs by day, week, month, and year.

Free estimate · No account needed
YOUR APPLIANCE

Estimate running cost

Make it easy to compare
Power detailsChoose values shown on the label
Enter the watt value
W · watts
per day
hours
per week
days
Check a recent bill
/ kWh
Enter the price for one kilowatt-hour (kWh) as shown on your bill.
YOUR ESTIMATE

Running cost

Estimated per month
—
Enter your details to see an estimate
Per day—
Per week—
Per year—
Power at this usage—
YOUR SHORTLIST

Compare appliances

Add appliances to see which ones use the most electricity.
Estimate only. Actual use can vary with settings, temperature, and appliance efficiency.

How to get a useful estimate

A quick calculation can help you spot which appliances deserve a closer look. Use the electrical values printed on the device label and the energy price from your latest bill.

1
Enter watts, or choose volts + amps. If your label shows volts and amps, select that option and WattWise estimates watts for you. A label may also show kW; 1 kW equals 1,000 W.
2
Estimate its hours and days. Use an average for the week, especially for devices that cycle on and off.
3
Use your price per kWh. Look for the energy charge on your bill. If your bill uses tiers, a single rate gives an approximation.

Common questions

How is the electricity cost calculated?

Watts are divided by 1,000 to get kilowatts. We multiply by hours of use, days used, and your price per kWh. Monthly and annual estimates use average calendar periods.

Where do I find the wattage?

Check the rating label, product manual, or manufacturer page. Some devices list volts and amps rather than watts; if so, watts are approximately volts multiplied by amps. Real-world draw may differ from the rated maximum.

Why is my bill different?

This estimate covers the energy charge for one appliance. Bills can also include fixed fees, taxes, delivery charges, variable rates, and other usage. Thermostats and automatic cycling can change actual consumption too.