Peak Level Analyzer — Peak vs RMS, Crest Factor & Headroom

A peak level meter measures two complementary quantities. Sample peak (also called peak amplitude) is the single highest sample value in each moment — it catches the brief spikes that decide whether you clip. RMS (root mean square) is the average energy over a short window and tracks how loud something sounds. The gap between them is the crest factor (peak ÷ RMS, shown here in dB): a pure sine wave is about 3 dB, natural speech and uncompressed music are often 12–20 dB, and heavily compressed or limited material is much lower. A high crest factor means punchy, dynamic audio; a low crest factor is the signature of the loudness war in over-compressed music.

Headroom is how far your loudest peak sits below 0 dBFS — the digital ceiling. Positive headroom is good; when peaks reach 0 dBFS you’re clipping, which the clip counter flags. Watching peak and RMS together tells you both whether you’re safe from clipping (peak) and how loud you actually are (RMS). For podcast recording, a target of around −18 dBFS RMS with a peak ceiling of −6 dBFS leaves comfortable headroom. For streaming platforms such as Spotify or YouTube, loudness normalization means the RMS relationship matters more than raw peak level. To check how this tool's peak readings relate to frequency content, pair it with the peak frequency detector.

Why dBFS, not SPL

These readings are in dBFS — decibels relative to digital full scale, where 0 is the maximum and quieter is negative. They are relative, because a browser microphone isn’t calibrated and the operating system may apply automatic gain control (AGC). That makes this perfect for checking headroom, spotting clipping, and comparing peak-to-RMS relationships — but it is not a calibrated environmental Sound Pressure Level (SPL) reading in dB or dBA. For calibrated loudness measurements, a dedicated sound level meter with a known reference microphone is required. You can also use the decibel meter on this site, which displays relative RMS levels with an intuitive gauge.

LUFS vs dBFS vs True-Peak: What Is the Difference?

dBFS (what this tool measures) is a sample peak level — it captures the highest individual sample value and says nothing about how loud audio sounds to a listener. LUFS (Loudness Units Full Scale) is different: it applies K-weighting to reflect human hearing sensitivity, then measures integrated loudness over time with a gating algorithm that ignores silence. That makes LUFS a measure of perceived loudness, which is why streaming platforms use it for normalization. Typical targets are around −14 LUFS for Spotify, YouTube, and Tidal, and −16 LUFS for Apple Podcasts. True-peak (dBTP) goes a step further: it oversamples the signal to catch inter-sample peaks that fall between actual samples and can exceed the sample peak — these can cause distortion when audio is transcoded to lossy formats. A true-peak ceiling of −1 dBTP is a widely used guard against that clipping on delivery. To measure integrated loudness directly, use the LUFS meter; to understand how platforms apply normalization to your mix, see the loudness normalization tool.