Ohm's Law Calculator

Use this Ohm's law calculator to quickly work out voltage, current, resistance and power in simple circuits. It is useful for electronics study, bench work, hobby projects, quick troubleshooting and checking homework or wiring assumptions before you move on.

Pick any two known values, enter the numbers and the tool solves the remaining electrical quantities using the classic relationships between volts, amps, ohms and watts. That makes it easier to compare source, load and power scenarios without repeating the same manual math.

The result works best as a practical reference for simple resistive DC circuits or first-pass estimates. In real projects, also consider tolerance, heat, AC behavior, power factor and the limits of the actual parts in the circuit.