Ohm's Law calculator to solve voltage, current, resistance, and power with V=IR, P=VI, P=I²R, and P=V²/R for circuits, LEDs, and electrical checks.
Use this Ohm's Law calculator to solve voltage, current, resistance, and power for a DC circuit. Enter any two known values and the calculator solves the other two using V = I x R, P = V x I, P = I^2 x R, and P = V^2 / R.
It is useful for common searches such as ohm's law calculator, voltage current resistance calculator, and LED resistor calculator. The unit selectors also make it practical for small electronics, power checks, and quick engineering calculations.
$$V = I \times R$$ $$P = V \times I$$
SI units for Ohm's law
| Variable | Symbol | SI Unit |
|---|---|---|
| Voltage | V | volt (V) |
| Electric current | I | ampere (A) |
| Electrical resistance | R | ohm (Ω) |
| Power | P | watts (W) |
Ohm's Law Calculator FAQ
Ohm's Law states that voltage equals current multiplied by resistance: V = I x R, where V is voltage, I is current, and R is resistance.
Rearrange the formula to I = V / R. If you know the voltage and resistance, the calculator divides voltage by resistance to get current.
Use R = V / I. This is useful for resistor sizing, quick circuit checks, and simple LED calculations.
You can use P = V x I, P = I^2 x R, or P = V^2 / R. The calculator picks the matching formula from the values you provide.
Four quantities are linked: voltage, current, resistance, and power. Any two known values determine the other two, so the calculator lets you solve the full set from a 2-of-4 input combination.
It supports common voltage, current, resistance, and power units such as V, mV, A, mA, ohm, kOhm, W, mW, and kW.
A common LED resistor formula is R = (Vsupply - Vled) / Iled. This calculator helps with the resistor value and the resistor power check when you know the supply voltage, LED drop, and target current.
It is useful for electronics homework, DC circuit checks, resistor sizing, LED wiring, power calculations, and quick troubleshooting when you know any two of the core electrical values.
