Free Key Finder for Beats

Detect the musical key of a beat or sample straight from the audio file. The analysis runs locally in your browser, and the result includes the relative key so you can see both readings.

No signup • 3 free scans a day • Your audio never leaves your browser

How key detection works

BeatTag converts a series of short slices of your track into a frequency spectrum and measures how much energy falls on each of the twelve notes, whatever the octave. This gives a profile of which notes the track uses most.

That profile is compared with standard major and minor key templates, and the closest match is reported along with a match percentage. This is a well-established method for estimating the key of polyphonic music.

Relative keys: why you see two answers

Every major key shares its notes with a minor key. A minor and C major use exactly the same seven notes, so a track built on those notes can reasonably be read either way. These pairs are called relative keys.

BeatTag reports its best match and shows the relative key next to it. Use your ears to decide which note feels like home: if the loop resolves to A, call it A minor; if it resolves to C, call it C major.

Why the key matters for producers

Knowing the key lets you pick compatible samples, tune vocals and instruments, and tell artists what they are working with. It is also a common detail in beat titles and descriptions, since artists and engineers often search by key and tempo together.

BeatTag writes keys using sharps, for example F# Minor. Gb Minor is the same key written with flats.

Limits you should know about

Key detection is an estimate. It is less reliable on beats that are mostly drums and 808 with very little melody, tracks that change key partway through, heavily detuned samples and atonal sound design.

When a result matters, confirm it against your piano roll or a tuner. For a quick first label on dozens of beats, it saves a lot of time.

Frequently asked questions

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