About this tool
Electricity Running Cost Calculator is a free, in-browser tool that turns an appliance's power rating into money: what it costs to run per day, per month and per year at your electricity tariff.
Energy used is watts ÷ 1000 × hours per day (in kWh), multiplied by your price per kWh for the daily cost, then by 30.44 for a monthly average and 365 for a year. A quantity field lets you cost several identical devices at once — say five 10 W light bulbs.
Check the label or a plug-in power meter for the real wattage, enter the price per kWh from your electricity bill, and compare an old appliance against an efficient replacement. Everything is calculated locally in your browser.
Frequently asked questions
Where do I find the wattage?
On the appliance's rating label, its manual, or a plug-in energy meter. Note that rated (maximum) wattage can exceed typical draw — fridges and washing machines cycle, so an average figure gives a better estimate.
Why is the month multiplier 30.44?
30.44 is the average number of days in a month (365.25 ÷ 12), which makes the monthly figure consistent with the yearly one.
What price per kWh should I enter?
Use the per-kWh unit rate from your electricity bill, in your own currency. If your tariff has peak/off-peak rates, use the rate for the hours the appliance actually runs.
Does the calculator work for standby power?
Yes — enter the standby wattage (often 1-10 W) and 24 hours per day to see what always-on devices cost you per year.