Kilowatt Hour Calculator
Convert power between watts and kilowatts, compute energy consumption in kWh, and estimate appliance electricity costs based on power rating and usage time.
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Applications
Calculate energy consumption and electricity costs for any appliance. Enter power rating, usage time, and electricity rate to get daily, monthly, and annual costs. Includes multi-appliance totals, CO₂ estimates, and power unit conversion.
The Formula
kWh = (Watts × Hours) / 1000. Monthly kWh = Daily kWh × 30.44. Annual kWh = Daily kWh × 365.25. Cost = kWh × Rate × Appliances. CO₂ = Annual kWh × 0.386 kg/kWh (EPA eGRID 2023 factor).
Fun Fact: The average US household uses about 886 kWh per month. A single space heater running 8 hours a day can add 3+ to your monthly bill during winter months!
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