Ohm's Law Calculator
Solve voltage, current, or resistance in a DC circuit.
Inputs
Loading calculator…
Calculating…
Was this helpful?
Formula
V = I × R
Ohm's law relates voltage (volts), current (amperes), and resistance (ohms). Power P = V × I is shown when solving for V or I.
Worked example
12 V across 6 Ω draws I = 12/6 = 2 A and dissipates 24 W.
Where this can give the wrong answer
- Zero resistance with non-zero voltage implies infinite current — unphysical; division by zero is blocked.
- Assumes ohmic (linear) resistors; LEDs and diodes are not ohmic.
- AC reactance and impedance need complex numbers, not this DC form.
FAQ
- Pick what to solve in the dropdown; enter the other two known quantities.