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Peak Voltage Calculator

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

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

A peak voltage calculator converts sine-wave RMS voltage or peak-to-peak voltage into peak voltage and shows the related waveform values beside the main result. It is useful when you need to translate mains-style RMS values or oscilloscope peak-to-peak readings into the crest amplitude a circuit actually sees.

What this peak voltage calculator solves

This page starts from the two waveform values users most often know before they need a peak figure. If you know RMS voltage, it multiplies by the square root of two to reach the positive crest. If you know peak-to-peak voltage, it divides by two to reach that same peak value.

Showing the supporting RMS and peak-to-peak values beside the answer makes the result easier to audit. That matters when you are comparing scope readings, signal-generator settings, and component voltage limits that may use different conventions.

The sine-wave formulas behind the result

For an ideal sinusoidal waveform, peak voltage equals RMS voltage times the square root of two. Peak-to-peak voltage equals twice the peak voltage, so dividing peak-to-peak by two gives the same crest amplitude directly.

Those relationships are specific to clean sine waves. The calculator keeps the two conversion paths separate so you can start from the quantity you actually have instead of converting through multiple manual steps.

Vpeak = Vrms x √2

Converts sine-wave RMS voltage into peak voltage.

Vpeak = Vpp / 2

Converts sine-wave peak-to-peak voltage into peak voltage.

Vpp = 2 x Vpeak

Shows the supporting peak-to-peak voltage that corresponds to the solved crest value.

How to use the result

Peak voltage is often the quantity you need when checking whether a waveform will exceed the safe input swing of a circuit, capacitor, or measurement instrument. RMS values are common on multimeters and mains systems, while peak-to-peak values often come from scopes and signal sources.

Seeing the related waveform values together helps avoid a common mistake: assuming a rated RMS value is already the waveform crest. A 120 V RMS sine wave, for example, actually reaches about 169.7 V peak and spans about 339.4 V peak-to-peak.

Where this simplified model stops

This calculator assumes an ideal sinusoidal waveform only. It does not model square waves, triangle waves, DC offsets, clipped signals, harmonic distortion, or crest-factor changes that alter the relationship among RMS, peak, and peak-to-peak voltage.

Use it as a planning and educational aid when the waveform is approximately sinusoidal. If the signal is distorted or intentionally non-sinusoidal, calculate or measure peak behaviour from the actual waveform instead.

Frequently asked questions

What is peak voltage?

Peak voltage is the maximum excursion of a waveform from zero to its crest. For a sine wave, peak voltage is higher than RMS voltage by a factor of √2.

 Why can I convert peak-to-peak voltage by dividing by two?

For a centered sine wave, peak-to-peak voltage is the full swing from negative crest to positive crest, so one peak is exactly half of that distance.

 Can I use this for square or triangle waves?

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

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