Tensão RMS
- Created by
- Renato Passos, Eng. de Software
- Reviewed by
- Renato Passos, Eng. de Software
Last updated: Apr 18, 2026
Formula
V_rms = V_pico/√2
About this calculator
The RMS Voltage Calculator converts the peak voltage of a sinusoidal alternating current (AC) signal into its RMS (Root Mean Square) value. The formula used is V_rms = V_peak / √2, valid only for pure sine waves. This tool is essential for engineers, technicians, and students working with AC circuits, as the RMS value represents the equivalent DC voltage that would produce the same power dissipation in a resistive load.
Operation is straightforward: enter the peak voltage value (in volts) and the calculator returns the corresponding RMS value. The constant √2 (approximately 1.414) is derived from integrating the sine wave over one complete cycle. For other waveforms, such as triangular or square waves, the peak-to-RMS relationship differs, so this calculator should not be used in those cases.
When to use? Whenever you need to determine the effective voltage of a sinusoidal AC source, such as household mains (127 V or 220 V RMS). It is also useful for sizing electronic components, calculating power in resistors, and analyzing audio circuits. Remember: the RMS value is what matters for most practical calculations, as it reflects the ability to do work.
Cautions: Ensure the input voltage is the peak value, not the peak-to-peak value. Peak-to-peak voltage (Vpp) is twice the peak value. Additionally, the formula assumes a perfect sine wave; harmonic distortions may invalidate the result. Always verify the waveform with an oscilloscope if in doubt.
Frequently asked questions
What is the difference between peak voltage and RMS voltage?
Peak voltage is the maximum value the waveform reaches, while RMS voltage is the equivalent DC value that produces the same power in a resistive load.
Can I use this calculator for square waves?
No, the formula V_rms = V_peak / √2 only applies to sine waves. For square waves, the RMS value equals the peak value.
How do I convert peak-to-peak voltage to RMS?
First divide the peak-to-peak value by 2 to get the peak value, then use the calculator. Example: Vpp = 10 V, then Vpeak = 5 V and Vrms = 5 / √2 ≈ 3.54 V.
Why is household voltage measured in RMS?
Because RMS represents the effective voltage that does work. A 127 V RMS outlet has a peak voltage of about 180 V, but the useful effect is equivalent to 127 V DC.
What if the waveform is not a pure sine wave?
The calculation may be inaccurate. Distorted waveforms with harmonics have a different peak-to-RMS relationship; use a True RMS multimeter for reliable measurements.