kWh Calculator — Free Online Calculator
Calculate kilowatt-hours (kWh) from watts and time. Free energy usage calculator for any appliance or device.
How to Use This Calculator
Enter the power consumption in watts and the duration in hours. The calculator converts to kilowatt-hours, the unit your utility company uses for billing.
The Formula Explained
kWh = Watts × Hours / 1000. One kilowatt-hour equals 1,000 watts used for one hour, or 100 watts for 10 hours.