Ohm's Law states that voltage (V) equals current (I) multiplied by resistance (R): V = I × R. It is the fundamental relationship in electrical circuits.

Voltage is measured in Volts (V), current in Amperes (A), and resistance in Ohms (Ω). Power is in Watts (W).

How is electrical power calculated?

Power (P) = Voltage × Current = V × I. It can also be expressed as P = I²R or P = V²/R.

What does resistance mean?

Resistance is the opposition to current flow in a circuit, measured in Ohms (Ω). Higher resistance means less current for a given voltage.

When does Ohm's Law not apply?

Ohm's Law applies to linear (ohmic) components. Non-linear components like diodes and transistors have variable resistance and require different models.

SCIScience

Ohm's Law

Calculate voltage, current, or resistance using Ohm's Law. Also computes electrical power.

Solve for

Current (I)

Resistance (R)

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How It Works

Formula

V = I \cdot R

I = \frac{V}{R}

R = \frac{V}{I}

P = V \cdot I

Where

$V$: Voltage(V)
$I$: Current(A)
$R$: Resistance(Ω)
$P$: Electrical power(W)

Select what to solve for: voltage (V=I×R), current (I=V/R), or resistance (R=V/I). Enter the two known values and the calculator finds the unknown plus the power (P=V×I).

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