🔌 Ohm’s Law Calculator
Solve for voltage, current, or resistance in a simple circuit using Ohm’s Law, and see the resulting power draw.
What this calculator does
Ohm’s Law describes the relationship between voltage, current, and resistance in an electrical circuit. Pick which quantity you want to solve for, enter the other two values, and this tool calculates the missing one along with the electrical power involved.
The formula
Ohm’s Law states V = I × R, where V is voltage in volts, I is current in amps, and R is resistance in ohms. Rearranging this equation gives I = V / R and R = V / I. Power is calculated separately with P = V × I, measured in watts.
This calculator assumes a simple direct-current circuit obeying Ohm’s Law. Real components, AC circuits, and non-linear devices (like diodes) can behave differently and are outside the scope of this basic tool.