RMS of a Signal Calculator

About this calculator

The root mean square (RMS) of a set of values is the square root of the average of their squares — a way of measuring the “typical” magnitude of a signal that properly accounts for both positive and negative values, unlike a simple average which can cancel them out or understate their real effect.

RMS matters most for anything involving power or energy: for an AC voltage or current, RMS is the value that delivers the same heating/power effect as an equivalent DC signal, which is why household power like “120V” actually refers to an RMS value, not the peak voltage. Electrical engineers and audio/signal-processing engineers use RMS to size components for real power dissipation, specify audio equipment loudness, and characterize noise and vibration signals where the peak alone would be misleading.