Song Key Finder

Estimate the major or minor key of a local song, see confidence and alternatives, and keep the recording on your device.

Choose a song or recording

Audio and detected notes stay in this browser. Nothing is uploaded.

MP3, WAV, OGG, FLAC, M4A, or AAC. Maximum 25 MB and five minutes.

Drop a local audio file here

or choose one from your device

.mp3, .wav, .ogg, .flac, .m4a, .aac · 25 MB · 5 minutes

Choose an audio file to begin.

How to find the key of a song

  1. 1. Choose a local recording. Select an MP3, WAV, OGG, FLAC, M4A, or AAC file. Your browser checks its size, duration, and codec without uploading it.
  2. 2. Detect pitched notes. Balanced sensitivity suits most material. Clean reduces weak artifacts; Detailed keeps more quiet and short detections.
  3. 3. Compare the likely keys. Review confidence, the nearest alternatives, relative and parallel keys, the scale, and the numeric pitch-class distribution.

From audio to a tonal-center estimate

The on-device model first estimates pitched notes from the waveform. Each non-drum pitch class is weighted by its detected duration and strength, so a sustained prominent note contributes more than a brief weak artifact.

That 12-note distribution is compared with all 24 catalog-trained major and minor profiles using correlation. The strongest match becomes the likely key; the runner-up gap helps keep the confidence label conservative.

Confidence is guidance, not certainty

Major and relative minor share seven scale notes, while parallel keys share a tonic. Sparse melodies and repeating riffs can fit several profiles. Low confidence is useful information: compare the alternatives, listen for cadences and resolution, and avoid treating a small score difference as a fact.

Modulation, modes, and difficult mixes

One global key cannot fully describe every song. Modulation, modal harmony, chromatic passages, borrowed chords, detuned instruments, percussion-heavy audio, room noise, and mastered full mixes can blur the pitch distribution or make different sections point elsewhere.

Version one ranks major and natural-minor profiles only. It does not label chords, recognize every mode, separate stems, or fabricate a modulation timeline. A short representative section can sometimes be more informative than a stylistically varied full track.

Local analysis and browser limits

Audio is decoded, resampled, transcribed, and compared locally. The 25 MB and five-minute limits bound device memory; the worker stops after 60 seconds without progress. Model assets load from Songparts only after you start analysis. No audio, detected MIDI, key result, microphone input, database row, or telemetry payload is uploaded.

FAQ

Is this song key finder free?
Yes. You can analyze a local recording without an account or payment.
Is my song uploaded?
No. The audio, decoded samples, detected notes, and key comparison stay in your browser. Songparts serves the analysis worker and pinned model files from the same site, but your recording is not sent to a server.
Which audio formats can I analyze?
Choose an MP3, WAV, OGG, FLAC, M4A, or AAC file up to 25 MB and five minutes. Actual codec support depends on your browser and operating system.
How does the key finder work?
A local note-detection model estimates pitch, duration, and strength. Songparts builds a 12-note pitch-class distribution and compares it with catalog-trained major and minor key profiles.
How accurate is automatic key detection?
It is an estimate. Clear tonal music with a stable tonic usually works best. Dense mixes, noise, sparse notes, detuning, and ambiguous harmony can lower confidence or favor a related key.
What do low, moderate, and high confidence mean?
Confidence combines how strongly the top profile fits and how clearly it beats the runner-up. Low confidence keeps alternatives prominent because several tonal centers fit similarly.
Why can the relative major or minor rank highly?
Relative major and minor keys share the same notes, so their pitch distributions can be very similar. Chord emphasis, bass movement, cadences, and melody determine which tonal center listeners hear.
Can a song have more than one key?
Yes. A song may modulate, tonicize other chords, or place sections in different keys. This version returns one global estimate and alternatives rather than inventing a section-by-section modulation map.
Does it recognize modes such as Dorian or Mixolydian?
No. Version one ranks the 12 major and 12 natural-minor keys. Modal songs may appear as a related major or minor key and often receive a lower-confidence result.
Does it identify chords or a chord progression?
No. It compares the overall detected pitch distribution. Use the likely key as a starting point, then verify chords and cadences by ear or in an instrument or DAW.
Which sensitivity should I use?
Balanced is the default. Clean favors stronger notes and fewer artifacts; Detailed retains more quiet and short notes but may also include more noise. Compare results if the recording is difficult.
What should I do if analysis stalls or finds no notes?
Cancel and retry with a shorter, clearer excerpt in a current desktop browser. Try Detailed sensitivity for quiet notes, or convert the source to a conventional PCM WAV if its codec is not supported.
How should I verify the result?
Listen for the note and chord that feel resolved, compare the top alternatives, play the suggested scales over the recording, and inspect different song sections before transposing or arranging.

Use the result