What is the Appliance Running Cost Calculator?
This calculator tells you how much electricity an appliance costs to run. By entering its power rating in watts, how many hours per day you use it, how many days per month, and the price you pay per kilowatt-hour (kWh), you get a clear breakdown of the daily, monthly and yearly cost — plus the energy consumed in kWh. The tool is currency-agnostic: just enter your local price per kWh and the cost figures use the same currency.
How to use it
Find the wattage on the appliance label or its specification sheet (e.g. a microwave might be 1000 W, a fridge around 150 W average draw). Enter the watts, estimate realistic daily usage hours, choose days per month (use 30 for a typical month or fewer for occasional use), and type your electricity tariff. Press calculate to see the running cost.
The formula explained
Electricity is billed in kilowatt-hours. One kWh is 1000 watts running for one hour. So we first convert watts to kilowatts by dividing by 1000, then multiply by hours of use to get kWh, then by days for the month total, and finally by your price per kWh:
$$\text{Cost} = \frac{\text{Watts}}{1000} \times \text{Hours/Day} \times \text{Days/Month} \times \text{Price/kWh}$$
Worked example
Suppose a 1500 W space heater runs 4 hours a day for 30 days at $0.20 per kWh. Energy per day = \((1500 \div 1000) \times 4 = 6\) kWh. Per month = \(6 \times 30 = 180\) kWh. Monthly cost = \(180 \times \$0.20 =\) $36.00. Over a year that is about $432.
FAQ
Where do I find an appliance's wattage? Look on the rating label, manual, or power supply. If only amps and volts are listed, watts = amps \(\times\) volts.
What if usage varies day to day? Use an average. For a fridge that cycles on and off, use its average power draw rather than peak wattage.
How do I find my price per kWh? Check a recent electricity bill — it usually lists a per-kWh unit rate. Use that number in the price field.
