Ohm's Law Calculator

Select value to solve for, enter the other two. Results update in real-time.

The Ohm's Law Calculator is a fundamental tool for electrical calculations, based on the principle V=IR, where V is Voltage, I is Current, and R is Resistance. This calculator allows users to solve for any one of these three variables by inputting the other two. It's essential for understanding and troubleshooting electrical circuits, including those found in HVAC systems. By selecting the desired variable to solve for and providing the known values, users can quickly find the missing electrical parameter.

Electrical Power Formulas: While Ohm's Law (V=IR) relates voltage, current, and resistance, electrical power (P, measured in Watts) can also be calculated using these values: P = V × I (Power = Voltage × Current), P = I² × R (Power = Current Squared × Resistance), or P = V² / R (Power = Voltage Squared / Resistance). These formulas are fundamental in electrical engineering and are essential for understanding energy consumption and component ratings in HVAC systems.

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Important Note

This calculator applies to DC circuits or AC circuits with purely resistive loads. For AC circuits with inductive or capacitive components, impedance (Z) replaces resistance (R), and phase angles become important. This tool does not cover power calculations (P=VI, P=I²R, P=V²/R).