Want to know what your air conditioner, space heater or gaming PC really adds to the power bill? Enter the appliance’s wattage (printed on its label or power brick), how many hours a day it runs, and the price you pay per kilowatt-hour (check your utility bill; the US average is about 17 cents). Tap a preset to fill in a typical wattage. The result shows the estimated cost per day, month and year, plus the kWh used. Real usage varies with thermostat settings and cycling, so treat this as an estimate.
How it works: kWh per day = watts ÷ 1000 × hours. Cost = kWh × price per kWh. Month uses 30 days, year uses 365 days. Appliances with a thermostat or compressor (fridges, AC, heaters) cycle on and off, so their real draw is often 30–60% of the label wattage; adjust “hours per day” down to compensate.