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Drop in the track
WAV, FLAC, MP3, M4A or OGG. The audio is decoded and analysed entirely on your device.
Drop in a track and get its tempo and musical key, with Camelot notation for DJ sets and honest confidence when the answer is ambiguous.
Tempo comes from onset autocorrelation and key from chroma correlation against Krumhansl key profiles, both computed on your device. Sparse arrangements, rubato playing and heavy swing genuinely resist automatic detection: when the maths is unsure, this tool says so instead of guessing confidently.
Runs in your browser. Your audio is decoded and analysed on your device, never uploaded.
WAV, FLAC, MP3, M4A or OGG. The audio is decoded and analysed entirely on your device.
BPM from the rhythm itself, key from the harmony, with the Camelot code DJs use for harmonic mixing next to the musical name.
When the pulse is soft or two keys score nearly alike, the tool says so and shows the runner-up instead of bluffing a single answer.
Tempo detection listens for the rhythm of energy: onsets. The track is reduced to a curve of how percussive energy arrives over time, and that curve is compared against itself at every plausible spacing. The spacing where it lines up best is the beat period. One honest complication: a track that lines up at 120 BPM also lines up at 60 and 240, and which one is right is a feel judgment. This tool picks the most musical reading and always shows the half and double-time alternates.
Key detection listens for the weight of pitches. Every moment of the track is folded into twelve bins, one per pitch class, and the resulting profile is compared against known profiles for all 24 major and minor keys, a method built on the Krumhansl key research. The tool also checks which pitch holds the lowest note as the track opens and resolves, because songs overwhelmingly start and end on their tonic, and that is often what separates a key from its relative.
Camelot notation maps the 24 keys onto a clock face so DJs can mix harmonically without music theory: neighbouring numbers and same numbers across the A/B rings blend cleanly. An 8A track mixes into 7A, 9A and 8B. The tool shows the code next to the musical key name.
Some songs genuinely resist a single answer. Loops that never sharpen their leading tone sit between a minor key and its relative major, and musicians argue about those by ear too. When the maths lands that close, the tool names both keys rather than pretending certainty, because a stated runner-up is more useful than a confident guess.
On steady material it lands within a fraction of a beat per minute. The genuine ambiguity is half versus double time, which is a feel judgment: the tool picks the most musical reading and always lists the alternates.
Because some tracks honestly sit between two keys, usually a minor key and its relative major, which share every note. When the scores land that close the tool names both. Musicians disagree about those songs by ear as well.
A DJ-friendly relabelling of the 24 keys onto a clock: 1A to 12A for minor keys, 1B to 12B for major. Tracks mix harmonically with neighbours on the wheel, so an 8A track blends with 7A, 9A and 8B.
Ambient, rubato and beatless material has no periodic onset pattern to measure. The tool says so instead of inventing a number; the key reading stands on its own.
It classifies into the 24 major and minor keys, which is what DJ software and most references use. Modal material resolves to its closest major or minor reading.
It is built for tracks, not mixes: one tempo and one key per file, with a 20 minute cap. Mixes change both mid-file, so analyse the individual tracks instead.
No. Decoding and analysis happen entirely on your device, and nothing is stored when you close the page.
Yes. Free to use, no account, nothing uploaded. It is one of a set of browser tools we build for artists and labels preparing releases.
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