How does the BPM & Key Finder work?
Your file is decoded in your own browser using the Web Audio API, then analyzed with two algorithms running locally — spectral-flux onset autocorrelation for BPM, and Harmonic Product Spectrum chroma analysis against Temperley's improved key profiles for the musical key. Nothing is uploaded to a server. Once detected, the result is mapped onto the Camelot Wheel so you can immediately mix in key.
Which file formats are supported?
Any format your browser can decode — MP3, WAV, AIFF, FLAC, M4A and OGG all work. For best accuracy, use a lossless file (WAV / AIFF / FLAC) — heavily compressed MP3s can shift the key detection by a semitone on tracks with a weak tonal center.
What is Camelot key notation?
Camelot notation translates the 24 musical keys onto a clock face (1A–12A for minor, 1B–12B for major). Tracks with adjacent Camelot numbers or matching numbers with the opposite letter mix harmonically — no clashing notes. Learn the rules on our interactive Camelot Wheel.
FAQ
Is this really free?
Yes. No signup, no watermark, no upload limit. The whole analysis runs inside your browser — DJCueX never sees your audio.
How accurate is the detection?
For modern electronic music with a clear kick pattern, BPM accuracy is typically >98%. Key detection sits around 85–90% on tonal genres (house, trance, melodic techno) and lower on heavily atonal or distorted tracks. Each result ships with a confidence score so you can spot-check.
Can I analyze multiple tracks at once?
Not on this page — for batch analysis, sign up for DJCueX free and every track you upload is auto-analyzed and exportable to Rekordbox.
Does this work on mobile?
Yes — but expect analysis to take 2–4× longer than on a laptop because the FFT runs on a single CPU core.