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Peak Amplitude / Level Analyzer

See the live sample peak and RMS level of your microphone side by side, the crest factor between them, and your headroom to full scale — with peak hold and clip detection.

ℹ Levels are relative dBFS, not calibrated dB SPL. A browser can’t know your mic’s sensitivity, and the OS may apply automatic gain — so use this for headroom, clipping and peak-vs-RMS relationships, not absolute loudness. Nothing is recorded or uploaded.

Microphone

Input device

Idle — press Start.

Live levels

PEAK—dBFS

RMS

—

Crest factor

—

Headroom

—

Peak

RMS

-60-48-36-24-120

Max peak

—

Clips

0

Elapsed

0:00

Peak, RMS, Crest & Headroom

Sample peak is the single highest sample value in each moment — it catches the brief spikes that decide whether you clip. RMS 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 is about 3 dB, speech and uncompressed music are often 12–20 dB, and heavily compressed material is much lower.

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).

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 system may apply automatic gain. That makes this perfect for checking headroom, spotting clipping and comparing peak-to-RMS — but it is not a calibrated environmental decibel (SPL) reading.

Frequently Asked Questions

What’s the difference between peak and RMS?

Peak is the highest instantaneous sample — it determines clipping. RMS is the average energy and tracks loudness. Peak is always at least as high as RMS; their difference is the crest factor.

What is a good crest factor?

It depends on the material, not "good vs bad." A sine is ~3 dB; natural speech and music often 12–20 dB; heavy compression or limiting pushes it down toward a few dB. A shrinking crest factor as you process audio means you’re compressing the dynamics.

What does headroom tell me?

How many dB your loudest peak is below the 0 dBFS ceiling. Keeping a few dB of headroom avoids clipping. If headroom hits 0 and the clip counter climbs, lower your input gain or source level.

Is this a true-peak (inter-sample) meter?

No — it shows sample peak, the highest actual sample. True-peak meters estimate peaks between samples by upsampling, which can be slightly higher. For catching obvious clipping and comparing levels, sample peak is plenty.

Why are the numbers negative?

It’s dBFS: 0 is the digital maximum and quieter sounds are negative. −6 dBFS is louder than −20 dBFS. This is the opposite of dB SPL, where bigger positive numbers mean louder.

Is my audio recorded?

No. The signal is analyzed in real time to compute the levels and is never recorded, saved, or transmitted. The microphone is released when you press Stop or close the tab.

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