Ohm's Law Calculator Online - Calculate Voltage, Current, Resistance, and Power

Ohm's Law is the basic relationship between voltage, current, and resistance in an electrical circuit: U = I × R. Knowing any two of the three values, you can always calculate the third, and at the same time, the circuit power using the formula P = U × I. This is how our calculator works: enter two known parameters - the remaining two (the third value and the power) they will be calculated automatically.

The calculator supports different units of measurement: from microamps to kiloamps for current, from milliohms to megaohms for resistance, and similarly for voltage, so you can enter values in a convenient format without recalculating them manually. At the same time, the power automatically selects the appropriate unit of measurement: from microwatts to megawatts, depending on the result.

The tool is useful when selecting a resistor for an LED, calculating the load on the power supply, checking the parameters of an electronic circuit, or just learning the basics of electrical engineering. It is enough to enter any two values - resistance, current or voltage, and the calculator will instantly show the remaining circuit parameters.