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Peak-to-Peak Voltage Calculator

Convert RMS or peak sine-wave voltage into peak-to-peak voltage with the supporting RMS and peak values shown beside the result.

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Peak-to-peak voltage calculator: convert RMS or peak voltage for sine waves

A peak-to-peak voltage calculator converts either RMS voltage or peak voltage into peak-to-peak voltage for a sinusoidal waveform. It is useful when you need to translate oscilloscope, mains, or signal-generator values into the voltage swing a circuit actually sees from crest to crest.

What this peak-to-peak voltage calculator solves

This page covers the two most common starting points for a sine-wave conversion. If you know RMS voltage, it first derives the peak value and then doubles that to find peak-to-peak voltage. If you already know peak voltage, it doubles that value directly.

Showing the supporting RMS and peak figures beside the final answer makes the conversion easier to audit, especially when you are comparing datasheet ratings with scope measurements or translating household RMS values into waveform amplitude.

The sine-wave relationships behind the result

For a sinusoidal waveform, RMS voltage equals peak voltage divided by the square root of two. Peak-to-peak voltage is twice the peak voltage. Combining those relationships gives the RMS-to-peak-to-peak conversion used in the first mode.

Those formulas are standard for clean sine waves. The calculator keeps the two paths separate so you can start from the quantity you actually know without doing the intermediate conversion yourself.

Vpeak = Vrms x √2

Converts sine-wave RMS voltage into peak voltage.

Vpp = 2 x Vpeak

Converts peak voltage into peak-to-peak voltage.

Vpp = 2 x Vrms x √2

Direct sine-wave conversion from RMS voltage to peak-to-peak voltage.

How to use the result

Peak-to-peak voltage is often the easiest way to compare an AC waveform with the allowable input swing of an amplifier, ADC front end, or oscilloscope range. RMS voltage is usually more familiar on power systems and multimeters, while peak voltage can appear in signal-generation and rectifier discussions.

Seeing all three values together helps prevent unit confusion. A 120 V RMS sine wave is not 120 V peak and not 120 V peak-to-peak; the waveform actually reaches about 169.7 V peak and 339.4 V peak-to-peak.

Where this simplified model stops

This calculator assumes a sinusoidal waveform only. It does not model square waves, triangle waves, clipped signals, DC offsets, harmonic distortion, or crest-factor differences that change the relationship between RMS, peak, and peak-to-peak voltage.

Use it as a planning and educational aid for clean sine-wave signals. If the waveform is distorted or intentionally non-sinusoidal, measure or calculate the relevant values from the actual waveform definition instead.

Frequently asked questions

What is the difference between RMS, peak, and peak-to-peak voltage?

RMS voltage is the effective heating-equivalent value, peak voltage is the waveform’s maximum excursion from zero, and peak-to-peak voltage is the full swing from the negative peak to the positive peak.

 Why is 120 V AC not the same as 120 V peak?

Because standard mains ratings are expressed in RMS volts. For a sine wave, 120 V RMS corresponds to about 169.7 V peak and about 339.4 V peak-to-peak.

 Can I use this for square or triangle waves?

No. The conversion factors on this page assume a sinusoidal waveform. Other wave shapes have different relationships among RMS, peak, and peak-to-peak voltage.

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