Power and energy describe different things
Watts describe a rate of energy use. Kilowatt-hours describe energy consumed over time. If a device draws a constant 1,000 watts for two hours, it uses 2 kWh:
1,000 W × 2 hours ÷ 1,000 = 2 kWh
That formula is useful only when the watts figure represents the power used during the entered runtime. A maximum or rated nameplate value may describe a limit or a particular operating condition rather than long-term average power.
Cycling changes the average
Refrigerators, air conditioners, heat pumps, and other controlled loads can cycle on and off. Variable-speed equipment can change power continuously. Treating a maximum watts figure as continuous draw can overstate energy use.
When an annual kWh figure based on a standardized procedure is available, use the annual-kWh mode for a label repricing task. For a watts calculation, prefer measured average power or measured energy across a representative period.
Estimate appliance electricity cost in the calculator. Choose Annual kWh for a yearly energy figure, or Average watts for measured average power and runtime. Enter your electricity price in cents per kWh to get monthly and yearly estimates.
Label your assumption
The watts mode annualizes the use pattern you enter. It does not infer duty cycle, standby consumption, seasonal operation, or appliance behavior. Keep a note of where the watts and runtime figures came from so the estimate can be reviewed later.
The calculator uses one electricity price you enter. It does not model tiered or time-of-use rates, taxes, or fixed charges. The result is an appliance energy-cost estimate, not your electricity bill.