Power Dissipation Calculator
Calculate electrical power and suggest a safe derated component wattage rating.
Inputs
Result
Example Inputs: V = 12V, R = 330 Ohms
Example Output: P ≈ 0.436W, recommended resistor rating >= 1W
Live Result: Enter values and click Calculate.
Formula
P = V * I, P = I^2 * R, P = V^2 / R; recommended rating = 2x calculated power
Worked Example
Use the example inputs and outputs above to walk through the calculation step-by-step.
FAQ
Which formula is used?
The calculator chooses from P = V * I, P = I² * R, or P = V² / R based on provided inputs.
Why is recommended rating higher than computed power?
It applies a 2x derating guideline to improve reliability and thermal margin.
Can I leave one field blank?
Yes. Provide any two of voltage, current, and resistance.
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View ProductFormula Notes
Use conservative derating to improve thermal reliability and component lifespan.
Worked Example
At 12V across 330 ohms, dissipation is around 0.436W, so 1W is a practical rating.