RMS Voltage Calculator
Convert peak voltage to RMS (root-mean-square) voltage for common waveform shapes like sine, square, and triangle waves.
What is RMS voltage?
RMS (root-mean-square) voltage is the effective value of an AC waveform — the equivalent steady DC voltage that would deliver the same average power to a resistive load. It’s why household mains voltage (like 120V or 230V) is quoted as an RMS value, even though the actual peak voltage is higher.
The formulas used
For a pure sine wave, Vrms = Vpeak / √2 (about 0.707 × peak). A square wave’s RMS voltage equals its peak voltage exactly, since it spends all its time at the extremes. A symmetric triangle or sawtooth wave has Vrms = Vpeak / √3 (about 0.577 × peak).
Enter the peak voltage and select the waveform shape to get the RMS value, average (rectified mean) value, and peak-to-peak voltage. This tool is for general electronics education and reference; real-world waveforms with noise or distortion may differ slightly from these ideal formulas.