Calculate crest factor, peak, RMS, PAPR and dB values for voltage or current waveforms, including sine, square, triangle, sawtooth and pulse.

Use voltage or current magnitudes in matching units.

Use absolute peak and total RMS over the same interval. PAPR assumes power proportional to voltage² or current².

Related Calculators

Crest Factor Formula

The following formula is used to calculate the crest factor:

CF = Vp / Vrms

Variables:

  • CF is the crest factor
  • Vp is the absolute peak magnitude of the waveform
  • Vrms is the root mean square (RMS) value of the waveform

To calculate the crest factor, divide the peak value of the waveform by its RMS value.

What is a Crest Factor?

Crest factor is the ratio of absolute peak magnitude to total RMS over the same measurement interval. It applies to voltage or current and is at least 1 for a nonzero signal. A larger value means a larger peak relative to RMS; it does not by itself measure signal quality or establish equipment safety. For a constant resistive load, PAPR = CF² and the decibel ratio is 20 log10(CF).

How to Calculate Crest Factor?

The following steps outline how to calculate the Crest Factor.

  1. First, determine the peak value (Vp) of the waveform.
  2. Next, determine the RMS value (Vrms) of the waveform.
  3. Use the formula CF = Vp / Vrms to calculate the Crest Factor (CF).
  4. After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem:

Use the following variables as an example problem to test your knowledge.

Peak value (Vp) = 5 volts

RMS value (Vrms) = 2 volts