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Audio Crest Factor Calculator
Compare peak and RMS levels on the same amplitude reference to interpret crest factor and peak-to-RMS ratio.
RMS level (dB, common reference): -120–0; Peak level (dB, common reference): -120–0
Inputs stay on this page and clear on refresh.
Audio Crest Factor Calculator
RMS level (dB, common reference): -18 Peak level (dB, common reference): -3
- Crest factor (dB)
- 15.000000
- Peak/RMS amplitude ratio
- 5.623413
- RMS amplitude fraction
- 0.125893
- Peak amplitude fraction
- 0.707946
Use peak and RMS readings from the same signal interval and the same amplitude reference. Enter −120 to 0 dB, with peak ≥ RMS. Crest factor = peak−RMS dB; peak/RMS amplitude ratio = 10^(crest/20). Linear RMS and peak fractions = 10^(level/20). Example: RMS −18 dB and peak −3 dB give 15 dB crest and ratio 5.623413. Six decimal places; tiny signed values round to zero. Meter conventions can differ: some RMS dBFS scales include a sine-wave calibration offset. Convert both readings to one amplitude reference first. This is not LUFS, dynamic range, true-peak measurement, clipping prediction or a compressor setting; this tool does not analyze audio.
Methodology
How it works
Use peak and RMS readings from the same signal interval and the same amplitude reference. Enter −120 to 0 dB, with peak ≥ RMS. Crest factor = peak−RMS dB; peak/RMS amplitude ratio = 10^(crest/20). Linear RMS and peak fractions = 10^(level/20). Example: RMS −18 dB and peak −3 dB give 15 dB crest and ratio 5.623413. Six decimal places; tiny signed values round to zero. Meter conventions can differ: some RMS dBFS scales include a sine-wave calibration offset. Convert both readings to one amplitude reference first. This is not LUFS, dynamic range, true-peak measurement, clipping prediction or a compressor setting; this tool does not analyze audio.
Method and assumptions documented by Techrider.live
2026-10-19
Frequently asked questions
Can I mix RMS, LUFS and true-peak readings?
No. Use peak and RMS amplitudes from the same interval and reference. LUFS is differently weighted; meter calibration and sample/true-peak methods can change the interpretation.