Overview
What Is Ohm's Law?
Ohm's Law describes the relationship between voltage, current, and resistance in an electrical circuit: V = I × R.
Calculate voltage, current, and resistance instantly.
Ohm's Law describes the relationship between voltage, current, and resistance in an electrical circuit: V = I × R.
Useful for circuit design, electronics coursework, or troubleshooting electrical circuits.
Input any two of voltage, current, or resistance.
The calculator solves for the missing value.
The calculated value updates automatically.
V = I × R, where V is voltage (volts), I is current (amps), and R is resistance (ohms).
I = V ÷ R
R = V ÷ I
It applies to ohmic (linear) components - some components like diodes and transistors don't follow this simple linear relationship.
Volts for voltage, amps for current, and ohms for resistance - the standard SI electrical units.
Not directly - this calculates V, I, or R. Power (P = V×I) would need a separate calculation.
It's a good conceptual tool, though household electrical work should follow proper safety codes and often requires a licensed electrician.
The calculator expects exactly two known values to solve for the third - entering all three may not produce a meaningful result.
No, calculations happen entirely in your browser.
Yes, completely free with no sign-up required.