Crest Factor

Enter Peak and RMS to compute Crest Factor (Peak ÷ RMS). Includes dB conversion, visualization, and Show Work.

How to Use

  1. Pick a quantity (Voltage, Current, or Generic).
  2. Enter Peak and RMS (or use Solve Mode to compute Peak or RMS from Crest Factor).
  3. Enable Auto-scale outputs if you want friendly units.
  4. Open Show Work to see formulas and steps in base units.
Waveform Lab View
Visual feedback: Peak marker + RMS band (idealized).
Peak
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RMS
—
CF
—
CF (dB)
—
Headroom: —
Idealized waveform view (for intuition): Peak vs RMS Crest Factor = Peak ÷ RMS. dB = 20·log10(CF).
Inputs & Settings
Compute Crest Factor (Peak/RMS) or solve Peak/RMS from a Crest Factor.
Crest Factor applies to any waveform where Peak and RMS are defined.
Units scale inputs/outputs; Crest Factor itself is unitless.
Peak magnitude (not peak-to-peak).
Root-Mean-Square value.
CF = Peak ÷ RMS (unitless).
dB = 20·log10(CF).
Show Work (step-by-step)
—
Work is shown in base units for clarity. Crest Factor is unitless.

Crest Factor Formulas

Definition: Crest Factor compares a waveform’s peak to its RMS value.

  • Crest Factor: CF = Peak ÷ RMS
  • Peak from RMS and CF: Peak = RMS × CF
  • RMS from Peak and CF: RMS = Peak ÷ CF
  • Crest Factor in dB: CF(dB) = 20 × log10(CF)
Notes: CF is always ≥ 1 for non-zero signals; CF is undefined if RMS = 0.

FAQ

What does a high Crest Factor mean?

It means the waveform has large peaks compared to its average power (RMS). Common in audio peaks, pulsed loads, and some switching signals.

Why do people use Crest Factor in dB?

dB makes ratios easier to compare. For example, CF ≈ 1.414 (sine) is about 3.01 dB.

Is Crest Factor the same as peak-to-peak?

No. Crest Factor uses Peak (one-sided) and RMS. Peak-to-peak is typically 2 × Peak for symmetric signals.

Does Crest Factor depend on units?

No. Peak and RMS must be in the same units, so the ratio cancels out (unitless).

Tool Info

Last updated:

Updates may include UI improvements, unit support, and calculation edge-case handling.