How does the calculator find power along with V, I or R?

Once voltage and current are both known (either given directly or solved from Ohm's Law), power is calculated as P = V × I. This is why the power output appears regardless of which of the three variables you solved for.

Does Ohm's Law apply to all components?

Ohm's Law (V = I × R) applies to 'ohmic' components with a constant resistance, such as standard resistors and wires. It does not directly apply to non-linear components like diodes, transistors or lamp filaments, whose resistance changes with current or temperature.

Ohm's Law Calculator

Solve for voltage, current or resistance using Ohm's Law.

How this is calculated

V = I × R; P = V × I

Assumptions used in this calculation

Constant resistance: Assumes an ohmic (linear) component whose resistance does not change with applied voltage, current or temperature.
DC circuit: The formula applies to direct current or resistive AC circuits; it does not account for reactance from inductors or capacitors.

About this calculator

The Ohm's Law calculator solves for voltage, current or resistance from the other two known values, and also shows the resulting power.

Worked example

I=2A, R=10Ω

Result: V = 20V, P = 40W

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About this calculator

Frequently asked questions

How does the calculator find power along with V, I or R?

Does Ohm's Law apply to all components?

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