MASTER CHECK
Drop your final mix. Get the full report in seconds — loudness, true peak, clipping, stereo, balance, tempo and key. The file never leaves your device. Nothing is uploaded, nothing is stored.
or tap to choose — WAV, MP3, FLAC, OGG, M4A
Verdict
Checks run 100% inside your browser (Web Audio). Loudness follows the BS.1770 K-weighting method used by streaming platforms; true peak is a 4× oversampled estimate. BPM and key are smart estimates read from the audio itself — trust your ears for the final call.
Check your master, find its BPM and find its key – free, in your browser
Master Check reads your finished mix the way streaming platforms will hear it. Drop in a WAV or MP3 and get integrated loudness (LUFS), true peak, clipped samples, loudness range, head and tail silence, stereo correlation and a full frequency balance – plus the tempo from the built-in BPM finder and the musical key from the song key finder.
How do I find the BPM of a song?
Drop the song into Master Check. The BPM finder follows the drum hits in the file and reports the tempo, folded into the normal 70-160 range. It is an estimate – songs with clear drums read most accurately.
How do I find the key of a song?
The same analysis builds a chroma profile of the notes in your track and matches it against all 24 major and minor key profiles. Use the key to tune 808s, pick samples in key and match acapellas.
What loudness should my master be?
About -14 LUFS integrated with a true peak of -1.0 dBTP or lower is the safe streaming zone. Master Check shows both, with a clear PASS, CHECK or FIX badge on every measure.
Is my audio uploaded anywhere?
No. Every check runs 100% inside your browser with the Web Audio API. Your file never leaves your device, and nothing is stored.
More free tools: All JHALLU tools · Master Check · Beat Maker · Stem Lab