One upload, a full technical readout: duration, sample rate, channels, approximate bitrate, peak level, estimated loudness, DC offset, and a clipping check — genuinely measured from your file, not guessed.
The Audio File Info Analyzer tells you everything measurable about an audio file: duration, true sample rate, channels, average bitrate, loudness (LUFS), loudness range, true peak, RMS, crest factor, clipping, DC offset, silence share, stereo correlation and width — and whether a ‘lossless’ file is really an upsampled MP3.
That last check is unique: lossy encoders low-pass the audio at a fixed frequency (about 16 kHz for 128 kbps MP3, 19–20 kHz for 192–320 kbps). A genuine lossless recording has content right up to the Nyquist limit, so a sharp cliff in its spectrum reveals a transcode.
The browser decodes the file at its true sample rate (read from the header, so 96 kHz files stay 96 kHz). Loudness and true peak follow ITU-R BS.1770-4. Effective bandwidth is found from the long-term average spectrum (4096-point FFT over up to 60 s) by locating the steepest drop of at least 18 dB over about 400 Hz above 8 kHz; stereo correlation is the Pearson coefficient of left and right; clipping counts runs of two or more samples at full scale; silence is the share of 50 ms blocks below −60 dBFS.
Detect MP3s masquerading as FLAC/WAV.
Verify levels, clipping and format.
Confirm loudness and stereo health.
Find out why a file sounds wrong.
| Reads | Any browser-decodable file |
|---|---|
| Sample rate | Read from the header, not resampled |
| Metrics | 13–16 including stereo health |
| Transcode check | Spectral cliff detection |
By its spectrum: lossy-sourced FLACs end at a lossy encoder’s low-pass frequency.
Peak level minus RMS level; low values mean heavy compression.
It's a count of samples that hit (or came within a hair of) full digital scale — a high count usually means the recording or a processing step pushed the level too hot and introduced audible distortion.
It's a fast RMS-based estimate, not a certified ITU-R BS.1770 loudness meter — good for a quick reference, not for meeting a broadcast/streaming loudness spec exactly.
It's back-calculated from file size and duration (size × 8 ÷ duration), which is exact for constant-bitrate files but only an average for variable-bitrate files.
This tool runs entirely in your browser using the Web Audio API. Nothing is uploaded, stored or shared — there is no server to send your file to, so it works offline once the page has loaded.
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