Watts to Joules Calculator
Calculate transferred energy from constant or interval-average power and time.
Formula
E = Pt
Power: 20 W · Operating duration: 30 s · Transferred energy ≈ (20 W)×(30 s)
How to use
- Enter power in watts or kilowatts.
- Enter the operating duration.
- Read energy in joules.
Examples
- 1 kW for 1 h transfers 3,600,000 J.
Frequently asked questions
Do watts and joules measure the same thing?
No. Watt measures power; joule measures energy.
What if power varies?
Enter its average over the same interval, or calculate separate intervals.
Does this estimate energy cost?
No. It calculates energy only; a tariff is a separate input.
Sources
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