Physics

Watt-hour Calculator

Find energy in watt-hours from power and time.

Calculated Output

Energy (Wh) 300

Energy (kWh) 0.3

Formula: Wh = power × hours

Step-by-Step Breakdown

1. Values used:

2. Power = 60 W

3. Time = 5

5. Energy = Power x Time = 60 x 5 = 300Wh

6. Energy = 0.3kWh

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The math behind it

Energy (Wh) = power (W) × time (h). Divide by 1000 for kWh, the unit on your electricity bill.

60 W bulb for 5 h → 300 Wh = 0.3 kWh.

Wh vs W?

Watts is the rate of energy use; watt-hours is the total energy used.