Wondering what key a song is in? Drop an MP3, WAV, M4A, OGG or FLAC file onto the key finder above and it names the most likely key, such as F# minor or Bb major, together with a confidence meter. Next to the key you get its Camelot code for harmonic mixing, the relative major or minor, and the tempo in BPM with the half-time and double-time alternatives. A ranked list shows the three strongest key matches, and a small chart shows how much each of the 12 notes appears in the track. The tool is free, needs no sign-up, and runs in your browser; your audio is never uploaded to a server.
Example result
Input
A three-minute MP3 of a mid-tempo indie pop song built on guitar, bass, drums and a sung melody.
Output
Key: F# minor, with the confidence meter a little past the halfway mark. Camelot: 11A (for harmonic mixing). Relative major: A major, 11B. Tempo: 118.0 BPM, or 59.0 / 236.0. Top matches: 1. F# minor, 11A, 81% 2. A major, 11B, 74% 3. B minor, 10A, 63% Pitch class profile: the tallest bars sit on F#, C# and A, with E and B close behind. The tonic bar (F#) is highlighted. A close second place for the relative major is normal.
Scores
How it works
How Key Finder works
- 01
Decode the file on your device
Your browser decodes up to the first four minutes of the file and mixes it to mono. Clips under five seconds or near-silent files get a message instead of a guess.
- 02
Build a pitch class profile
The audio is cut into short overlapping windows. In each one, spectral peaks between roughly 55 Hz and 5 kHz are folded onto the 12 note names (C, C#, D and so on), octave ignored, and added up across the song. That summed profile is the bar chart you see under the result.
- 03
Compare it with all 24 keys
The profile is correlated with the Krumhansl-Kessler reference profiles for every major and minor key. The closest match becomes the answer, and the gap between first and second place feeds the confidence meter.
- 04
Estimate the tempo
Separately, the first 90 seconds are scanned for a steady pulse. If one is found you see the BPM plus its half and double values; if the beat is too loose, the tempo box says so.
Use cases
Who it is for
DJs planning harmonic mixes
Check the Camelot code of each track before a set. Staying on the same number, or moving one step around the wheel, keeps transitions free of clashing notes.
Musicians learning a song by ear
Know the key before you pick up an instrument, so you can guess the likely chords and stop hunting for the first note.
Producers sampling or remixing
Get the key and BPM of a sample or acapella before building around it, and see whether it needs pitching or time-stretching.
Singers choosing a key
See what key the original recording uses, then decide whether to transpose it up or down to suit your range before you rehearse with a band or backing track.
Tips
Get better results
- Use the full mix, not a drum loop or spoken intro; the key comes from harmony and melody.
- If the top two matches are a major key and its relative minor, listen for where phrases feel at rest. The chord a chorus resolves to is usually the tonic.
- Songs that change key partway through give a blended answer. Trim the file to one section and run each part on its own.
- A low confidence reading often means heavy distortion, lots of percussion or a modal or atonal piece. Check the top three on an instrument.
Limitations
What it can't tell you
The key finder recognizes the 24 major and minor keys only. It does not name modes such as Dorian or Mixolydian, blues or pentatonic scales, or tunings outside standard A440, so a track in D Dorian may come back as D minor or C major. It reports one key for the analyzed part of the file, so songs that modulate get an average. Recordings tuned between semitones can land on a neighboring key. For scales and modes, use the AI scale finder instead.
Frequently Asked Questions
Key Finder questions
How do I find the key of a song?
Drop the audio file onto the key finder at the top of this page. It reads the notes in the recording, compares their balance with all 24 major and minor keys, and shows the best match within a few seconds. You can confirm it by playing the tonic note on an instrument along with the track: the right note sounds settled rather than tense.
Is the key finder free, and is my audio uploaded?
Yes, it is free with no sign-up and no limit on how many files you check. All analysis happens inside your browser with the Web Audio API, so your audio is never uploaded to our servers. That makes it safe for unreleased demos.
What is the Camelot code next to the key?
The Camelot wheel numbers the keys from 1 to 12 and marks minor keys with A and major keys with B. Keys with the same number, or numbers next to each other, share most of their notes, which makes them easy to mix. For example, 8A is A minor and 8B is C major.
Why does it show a major key and its relative minor so close together?
A major key and its relative minor, such as C major and A minor, use exactly the same seven notes. The tool separates them by which notes are emphasized, like the tonic and fifth. When a song leans on both, their scores end up close, and your ear is the best tiebreaker.
Can it find the key and BPM together?
Yes. Every result includes a tempo estimate from the first 90 seconds, shown with half and double values in case the pulse reads twice as fast or slow as you count it. For a closer look at tempo, including tap tempo, use the BPM finder.
Related tools
You might also need
BPM & Tempo Finder
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Scale & Mode Detector
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Key & Chord Progression Analyzer
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Pitch Detector
Detect the musical note, frequency and cents offset of a voice or instrument in real time
Song Structure Analyzer
Detailed breakdown of verses, choruses, bridges, intros, and outros
Key Finder runs in your browser. LindaleAI's AI analysis tools use credits from a paid plan. See pricing