Ohm’s Law Calculator & Formula – Voltage, Current, Resistance
Free interactive Ohm’s Law calculator. Instantly calculate voltage (V), current (I), resistance (R), and power (P) with standard formulas, examples, and FAQs.
⚡ Interactive Ohm’s Law Calculator
Enter any two known values to instantly calculate the remaining values and total power dissipation.
Frequently Asked Questions (FAQs)
Q1: What is the primary equation for Ohm’s Law?
The primary equation is V = I × R, where V is Voltage in Volts, I is Current in Amperes, and R is Resistance in Ohms.
Q2: How do you calculate electrical power using Ohm’s Law?
Electrical power in Watts (W) measures energy consumption per second. By combining Ohm’s Law with the power law, power can be calculated using three formulas: P = V × I, P = I² × R, or P = V² / R.
Q3: What happens to current if resistance doubles while voltage stays constant?
According to the formula I = V / R, current is inversely proportional to resistance. If resistance doubles while voltage remains unchanged, the current flowing through the circuit is reduced by half.
Q4: Can Ohm’s Law be used for Alternating Current (AC) circuits?
Yes, for purely resistive AC circuits (such as heaters or incandescent bulbs). For AC circuits containing inductive or capacitive components, resistance (R) is replaced by total Impedance (Z), giving the equation V = I × Z.