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Audio Peak Headroom and Crest Factor

Compare a measured sample or true peak with a chosen ceiling, or calculate peak-to-RMS crest factor using compatible digital levels.

Use this result well

Inputs that matter
Peak measurement scale, Measured peak level, Chosen peak ceiling, Sample peak (dBFS), and 1 more
Output to expect
Peak margin, Crest factor
  • Check the units and required inputs before comparing results.
  • Keep the assumptions with a copied result so you can reproduce the calculation later.
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Reference & details

How it works

Peak margin to an explicit ceiling

Margin (dB) = chosen ceiling − measured peak; a negative margin means the peak exceeds the ceiling A level difference, not an audio processor. A true peak may exceed 0 dBTP even when stored samples are below full scale. A margin does not prove that the microphone, preamp or earlier processing stage did not clip. Use the separate crest-factor mode for compatible peak and RMS measurements.

Peak-to-RMS crest factor

Crest factor dB = sample peak dBFS − RMS dBFS Peak-to-RMS crest factor only. This is not EBU loudness range, integrated LUFS, signal-to-noise ratio or a loudness compliance test. Some RMS meters use a sine-calibrated 3.01 dB offset; normalize references before comparing. No universal healthy-dynamics threshold or compression recommendation is applied.

Updated: September 2026

Example Scenarios

Compare a measured sample peak or true peak with a ceiling expressed on the same scale. This is separate from peak-to-RMS crest factor.

Compare the sample peak and RMS of the same signal interval using an unshifted, matching amplitude reference.

Common Mistakes to Avoid

Applying peak margin to an explicit ceiling outside its stated assumptions

A true peak may exceed 0 dBTP even when stored samples are below full scale. A margin does not prove that the microphone, preamp or earlier processing stage did not clip. Use the separate crest-factor mode for compatible peak and RMS measurements.

Applying peak-to-rms crest factor outside its stated assumptions

This is not EBU loudness range, integrated LUFS, signal-to-noise ratio or a loudness compliance test. Some RMS meters use a sine-calibrated 3.01 dB offset; normalize references before comparing. No universal healthy-dynamics threshold or compression recommendation is applied.

FAQ

No. Check every relevant stage and listen to the recording.

No. Integrated loudness, peak level and crest factor are different measurements.

No. Loudness range uses a different loudness measurement method.

Not with this same-interval, unshifted amplitude reference. Check the meter reference and interval.

A silent signal has no finite logarithmic RMS. Do not invent a finite reading for it.

About Audio Peak Headroom and Crest Factor

Compare a measured sample or true peak with a chosen ceiling, or calculate peak-to-RMS crest factor using compatible digital levels. Choose the mode that matches your measurements or study design, enter the stated units and keep the method and limits with the result.