Knowing the key of a beat helps you write a melody that fits, choose samples that sit in tune and plan DJ transitions that don’t clash. This free song key finder listens to your file and tells you the key, its Camelot code and the neighbouring keys that mix well with it.
How it works
- Choose an audio file from your phone or computer (MP3, WAV, M4A or AAC work in every modern browser; FLAC and OGG work in most).
- Your browser decodes the audio and analyses it on your device. Nothing is uploaded to Centertainment or anyone else.
- Tempo comes from the rhythm: we track where new sounds start and look for the beat spacing that repeats most strongly.
- Key comes from the notes: we add up which of the 12 pitch classes sound most across the track and compare the result with published major and minor key profiles.
- You get the BPM, the key, its Camelot and Open Key codes, half-time and double-time values, the keys it mixes well with and a confidence level for each result.
Frequently asked questions
How does the song key finder work?
It measures how strongly each of the 12 notes sounds across the track, corrects for detuned audio, and compares that pattern with major and minor key profiles published by music psychologists (Krumhansl and Kessler, and Temperley). The closest match is the key.
Why does it sometimes give the relative major or minor?
A minor and C major use exactly the same notes, as do every minor key and its relative major. The difference is which note feels like home, and a short loop can lean either way. That's why we show the next-best key too.
My beat is detuned. Will it still work?
Yes. We estimate how far the audio is from standard tuning (A = 440 Hz) and correct for it before finding the key. If the tuning is off by more than about 10 cents, we tell you by how much.
How accurate is it?
It works best on music with a steady beat and clear chords. In our tests on synthesised loops with a known tempo and key, it found the right key every time and matched the tempo to within 0.5 BPM, except that some very slow or very fast loops were read at exactly half or double speed. Real songs are harder: tempo changes, live drumming, heavy distortion or songs that switch key can confuse any detector, and some tracks are read at half or double their tempo. Check the confidence level and the half-time and double-time values, and trust your ears.
Is my audio uploaded anywhere?
No. The file is opened and analysed inside your browser on your own device. It is never sent to Centertainment or any other server, which makes it safe for unreleased beats.
Which file types work?
Anything your browser can play: MP3, WAV, M4A and AAC work almost everywhere, and FLAC and OGG work in most browsers. You can also choose an MP4 video and we'll analyse its soundtrack. Files up to 150 MB and up to 10 minutes of audio are analysed.
How we find the key
The analyser measures how strongly each of the 12 notes appears across the track, then compares that pattern with major and minor key profiles published by music researchers (Krumhansl and Kessler, and Temperley). The key whose profile matches best wins. We also show the next-closest key, because a song in A minor and one in C major use exactly the same notes and short loops can lean either way.
Detuned beats
Plenty of beats are slightly sharp or flat, especially ones built from pitched samples. Before matching keys, Beat Lab estimates how far the audio sits from standard tuning (A = 440 Hz) and corrects for it. If your file is off by more than about 10 cents, the result tells you by how much, which helps when you tune a vocal or instrument to it.
Finding the key in your DAW
FL Studio, BandLab and Logic don’t all show a key for audio clips. A quick workaround is to export or bounce the beat as an MP3 or WAV and drop it here. Then set your piano roll or scale tool to the key shown.
Planning a DJ set? Open the result on our Camelot wheel, and get the tempo with the BPM finder.