When Ohm's law is enough
This calculator is useful for simple DC or resistive circuit estimates. Motors, LEDs, AC impedance and nonlinear components need more specific models.
Example
If current is 2 amps and resistance is 12 ohms, voltage is V = 2 x 12 = 24 volts. Power is P = 24 x 2 = 48 watts.
Common mistakes
Use amps, volts and ohms consistently. Milliamps must be converted to amps before using the formulas.
Limitations
This calculator assumes a linear resistive load. It is not suitable for mains safety decisions, complex AC circuits, batteries under load or electronic component design by itself.
Last reviewed: 2026-05-17