Resistor Power Dissipation Calculator

This calculator estimates the power dissipated in a resistor using Ohm’s Law. You can enter either the voltage across the resistor and its resistance, or the current through it and the resistance.

What this calculator is doing

Resistors convert electrical energy into heat, and it's important to calculate the power they dissipate to avoid damage or overheating. Power can be calculated using Ohm's Law in several equivalent forms:

$$ P = \frac{V^2}{R} $$

$$ P = I^2 \cdot R $$

$$ P = V \cdot I $$

Where:

$ P $ is the power in watts (W)
$ V $ is the voltage across the resistor in volts (V)
$ I $ is the current through the resistor in amps (A)
$ R $ is the resistance in ohms (Ω)

Use the equation that matches the values you know. This helps determine the minimum required resistor wattage rating.

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Disclaimer: These calculators are provided for informational purposes only. Always verify your designs against relevant engineering standards and consult a qualified professional. We do not take responsibility for any errors or damages resulting from the use of these calculations.