Peak-to-Peak Voltage Calculator – Convert AC Voltage Measurements

Convert between peak, RMS, average, and peak-to-peak voltage for sine waves.

Input Type

Voltage (V)

How to Use This Peak-to-Peak Voltage Calculator

Select your input type

Choose whether you have peak voltage, RMS voltage, or average voltage.

Enter the voltage value

Input your known voltage value. The calculator will convert to all other measurements.

Click Convert

Get peak-to-peak, peak, RMS, and average voltage values for a sine wave.

AC Voltage Conversion Reference

From	To Peak-to-Peak	To Peak	To RMS
Peak (Vp)	Vpp = 2 × Vp	Vp = Vp	Vrms = Vp / √2
Peak-to-Peak (Vpp)	Vpp = Vpp	Vp = Vpp / 2	Vrms = Vpp / (2√2)
RMS (Vrms)	Vpp = 2√2 × Vrms	Vp = √2 × Vrms	Vrms = Vrms
Average (Vavg)	Vpp = π × Vavg	Vp = π/2 × Vavg	Vrms = π/(2√2) × Vavg

Understanding AC Voltage Measurements

Peak Voltage (Vp)

Peak voltage is the maximum voltage measured from zero to the highest point of the sine wave. It represents the amplitude of the AC signal. For a 120V RMS household outlet, the peak voltage is about 170V.

Peak-to-Peak Voltage (Vpp)

Peak-to-peak voltage measures from the negative peak to the positive peak — the full vertical span of the waveform. It equals twice the peak voltage. Oscilloscopes typically display peak-to-peak values.

RMS Voltage (Vrms)

RMS (Root Mean Square) voltage is the DC equivalent that would deliver the same power to a resistive load. When we say "120V AC," we mean 120V RMS. For sine waves, Vrms = Vp / √2 ≈ 0.707 × Vp.

Average Voltage (Vavg)

Average voltage is the mean value over one half-cycle of a rectified sine wave. For a full sine wave, the average is zero (equal positive and negative halves). Vavg = 2/π × Vp ≈ 0.637 × Vp.

Common AC Voltage Examples

US Household Power (120V RMS)

Vp = 170V, Vpp = 340V, Vavg = 108V. The actual voltage swings from -170V to +170V, 60 times per second.

European Household Power (230V RMS)

Vp = 325V, Vpp = 650V, Vavg = 207V. Higher voltage means more power delivery with less current.

Audio Line Level (1V RMS typical)

Vp = 1.41V, Vpp = 2.83V. Professional audio uses +4dBu (1.23V RMS), consumer uses -10dBV (0.316V RMS).

Transformer Secondary (12V RMS)

Vp = 17V, Vpp = 34V. After rectification and filtering, you get about 17V DC minus diode drops.

Frequently Asked Questions

Why is RMS voltage used for AC power ratings?

RMS voltage gives the same heating effect as an equivalent DC voltage. A 120V RMS AC source delivers the same power to a resistor as 120V DC. This makes RMS the practical choice for power calculations and equipment ratings.

What's the difference between Vpp and Vp?

Peak voltage (Vp) measures from zero to the maximum. Peak-to-peak (Vpp) measures from the negative peak to the positive peak. For symmetric waveforms, Vpp = 2 × Vp.

Do these conversions work for all waveforms?

No. These formulas apply only to pure sine waves. Square waves, triangle waves, and complex waveforms have different relationships between peak, RMS, and average values.

Why is average voltage calculated from half-cycle?

A full sine wave averages to zero because positive and negative halves cancel. For practical purposes (like rectified power supplies), we use the average of the absolute value over a half-cycle.

What does √2 equal in the RMS formula?

√2 ≈ 1.414. So Vrms = Vp / 1.414 ≈ 0.707 × Vp. Conversely, Vp = 1.414 × Vrms. For 120V RMS: Vp = 1.414 × 120 = 170V.

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Peak-to-Peak Voltage Calculator – Convert AC Voltage Measurements

Peak Voltage (Vp)

Peak-to-Peak Voltage (Vpp)

RMS Voltage (Vrms)

Average Voltage (Vavg)

Frequently Asked Questions

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