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Crest factor measures how "peaky" a signal is relative to its overall power level — applicable to any waveform, not just a sine wave, since it works directly from measured peak and RMS values rather than assuming a specific waveform shape.
How it works
Enter the measured peak value and RMS value of your signal, and the calculator applies Crest Factor = Peak ÷ RMS.
- Enter peak value.
- Enter rMS value.
- Click Calculate to see your results.
Examples
Confirming a sine wave
A peak of 10 and RMS of 7.071 gives a crest factor of exactly 1.414 (√2) — the signature value for a pure sine wave; a pulse-like signal with sharp, brief peaks would show a much higher crest factor for the same RMS level.
Who should use it
- Audio engineering and signal analysis.
- Sizing power electronics and measurement equipment for peaky signals.
Industry applications
- Audio engineering and acoustics
- Power electronics and instrumentation
Advantages
- Works for any waveform shape, not just sine waves.
- Simple, direct calculation from two measured values.
Limitations
- Requires you to already have accurate peak and RMS measurements — it doesn't derive them from a waveform shape assumption.
Common mistakes to avoid
- Assuming every signal has the same peak-to-RMS ratio as a sine wave — many real-world signals (audio, digital pulses, switching waveforms) have very different crest factors.
- Mixing up peak and peak-to-peak values when entering the peak field — this tool expects true peak, not peak-to-peak.
Best practices
- Use real measured peak and RMS values from an oscilloscope or meter, rather than assumed sine-wave-derived figures, when you need an accurate crest factor.
- Consider crest factor when sizing equipment (amplifiers, power supplies) that needs headroom for a signal's peaks, not just its average level.
Tips
- If your result comes out close to 1.414, that's a good sign your signal is close to a pure sine wave — a result well above that indicates a peakier, non-sinusoidal signal.