Kwh Calculator
Calculate energy consumption in kilowatt-hours based on power and time, or estimate cost.
Published by:
isCalculator Editorial Team
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How to use this tool?
How to Use the kWh Calculator
- Enter Power (Watts): Input the power consumption of your device in watts (e.g., 1000 for a 1 kW appliance). Use positive numbers only.
- Enter Time (Hours): Input the duration the device runs in hours (e.g., 5 for 5 hours). Use positive numbers only.
- Enter Rate (Optional): If you know your electricity cost per kilowatt-hour (e.g., 0.12 for $0.12/kWh), enter it to calculate the total cost. Leave blank if not needed.
- Click "Calculate": Press the button to see results.
- Read Results:
- Energy (kWh): Shows the total energy consumed (Power × Time ÷ 1000).
- Cost ($): Shows the estimated cost (Energy × Rate), only if a rate was provided.
- Formula: Displays the calculation steps for clarity.
Note: All inputs must be non-negative numbers. The calculator uses watts and hours; no unit conversion is needed.
Previous Results
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Frequently Asked Questions
A kilowatt-hour (kWh) is a unit of energy equal to 1,000 watt-hours. It is commonly used to measure electrical energy consumption.
Multiply the power in watts (W) by the time in hours (h) and divide by 1,000. Formula: kWh = (W × h) / 1000.
Yes, if you enter a rate per kWh (e.g., $0.12), the calculator will also display the estimated cost.