What is Song Key Finder?

Analyzes audio to detect the musical key and scale. DJs use it for harmonic mixing, and producers use it to match samples to the right key.

Drop an MP3, WAV, OGG, FLAC, or AAC file (or record up to 8 seconds from your mic). The analyser builds a chromagram (energy across the 12 pitch classes), compares it against the Krumhansl-Schmuckler tonality profiles, and reports the most likely key plus its Camelot wheel notation (e.g. 8A for A minor). A confidence score tells you how clearly the song sits in that key.

How to use

1. Upload an audio file (MP3, WAV, OGG, FLAC) or record directly from your microphone
2. Wait a few seconds while the audio is analyzed
3. View the detected key, scale, BPM estimate, and Camelot notation for DJ mixing

When to use

• DJ sets where you want every transition to be harmonically compatible.
• Producers matching a vocal sample or melodic loop to the right key before chopping it in.
• Cover-band rehearsal — figuring out the key of a song from a recording instead of by ear.

Result

A DJ wants to mix two tracks harmonically. Upload the first track — it detects A minor (8A Camelot). Now you know compatible keys are 7A, 8A, 9A, or 8B for smooth transitions.

FAQ

How accurate is the key detection?

Around 80-90% for typical pop, rock, and electronic music with a clear tonal centre. Drops to about 60% on jazz with frequent modulations and ambient or atonal tracks. The confidence score reflects this — under 50% means the algorithm isn't sure, often signalling a modulation or weak tonality.

What's Camelot notation and why do DJs care?

Camelot maps each key to a number plus A (minor) or B (major) arranged on a wheel. 8A is A minor; the keys at 7A, 9A, and 8B mix harmonically without dissonance. DJs use it because two compatible Camelot numbers means the next track won't clash with the current melody.

Why is the detected key different from what I see on the song's Wikipedia page?

Relative major and minor share the same notes (C major and A minor, for example), so the algorithm can flip between them based on which note is more emphasised. A song labelled C major might detect as A minor if the verse leans on the A. Both are technically right.

Can it detect key changes within a song?

This version reports a single overall key. If a song modulates from C to D in the bridge, it'll pick whichever key dominates the audio you provided. To analyse one section, trim the audio to just that section in any editor first.

Why does the BPM detection give different results on the same track?

Some tracks have ambiguous tempo (half-time vs full-time feels). The algorithm picks the strongest peak in the autocorrelation, but if a song's drums sit on a half-time pulse, it might detect 70 instead of 140. Both are mathematically correct — double or halve as needed.

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