⚡ Electrical Physics & Electronics
Ohm's Law & Electricity Converter
Enter any two known parameters (Voltage, Current, Power, or Resistance) to calculate the remaining two values instantly.
Tip: Enter any 2 values to compute the rest.
Computed Electrical Parameters
Enter any two values above...
Ohm's Law and the 12 Fundamental Formulas
Formulated in 1827 by German physicist Georg Simon Ohm, Ohm’s Law is the foundational principle of electrical engineering. It states that the electrical current ($I$) flowing through a conductor between two points is directly proportional to the voltage ($V$) across the two points, inversely proportional to the resistance ($R$) between them.
The Complete Ohm's Law Formula Wheel
| Target Variable | Formula using $V$ & $I$ | Formula using $I$ & $R$ | Formula using $V$ & $R$ | Formula using $P$ & other |
|---|---|---|---|---|
| Voltage ($V$, Volts) | $V = P / I$ | $V = I \times R$ | $V = \sqrt{P \times R}$ | $V = P / I$ |
| Current ($I$, Amperes) | $I = P / V$ | $I = V / R$ | $I = \sqrt{P / R}$ | $I = P / V$ |
| Resistance ($R$, Ohms) | $R = V / I$ | $R = P / I^2$ | $R = V^2 / P$ | $R = V / I$ |
| Power ($P$, Watts) | $P = V \times I$ | $P = I^2 \times R$ | $P = V^2 / R$ | $P = V \times I$ |
Frequently Asked Questions
Yes, but with an important addition: in AC circuits containing capacitors or inductors, resistance ($R$) is replaced by impedance ($Z$), which accounts for phase shifts between voltage and current: $V = I \times Z$. For purely resistive AC loads (like heaters and incandescent lights), standard Ohm's law applies directly with RMS values.
According to Joule's First Law ($P = I^2 R$), the rate of thermal energy dissipation increases with the square of current. If current doubles through a fixed resistance, the heat generated increases fourfold, which is why wire gauge sizing is essential in home and industrial electrical installations.