Drop an audio file to instantly detect its musical key, tempo, and integrated loudness. Everything runs in your browser — nothing is uploaded. Use detection as a starting point; your ears and the song's context always win.
Key detection works by computing a chromagram — the total energy on each of the 12 pitch classes (C, C♯, D, …, B) across the whole file. That 12-value profile is then compared against the classic Krumhansl-Kessler key profiles for all 24 possible major and minor keys. The best match wins.
Tempo detection looks at the onset envelope — a running measure of how much new energy is appearing in the signal — and finds the periodicity that explains it best. Most reliable on rhythm-heavy tracks with a clear beat.
Loudness (LUFS) is a rough integrated RMS approximation (not a true EBU R128 meter, which needs K-weighting and gating). Use it for comparison, not mastering sign-off.
Expect ~85% accuracy on modern music. Confidence drops on ambiguous modal tracks, heavy pitch-shifting, or monophonic material. Always trust your ears over the number.