Free tools for your next audio edit
Find a song’s key. Estimate. Listen. Check.
Analyze a representative short MP3 or WAV section locally and compare possible major and minor keys. The result is an estimate, not a guaranteed answer.
Estimate a song’s key
Free · localChoose a supported file. No audio upload or account required.
Estimates one major or minor key from the selected section. Songs with modulations, nonstandard tuning, modal harmony, percussion or few pitched notes can give a misleading result or no result. The highest candidate is not guaranteed to be correct. This analyzes one channel and does not identify the song, chords, BPM or exact tuning. Browser decoding support varies.
Choose, estimate, verify
How to find a song’s key
- 01 / OPEN
Choose an audio file
Select a mono or stereo MP3 or WAV up to 50 MiB and five minutes. Playback, decoding and analysis happen locally in your browser.
- 02 / ANALYZE
Choose a musical section
Enter a start time with at least eight seconds remaining. Up to 30 seconds are analyzed. Choose a representative passage with chords and melody, rather than a drum-only intro.
- 03 / CHECK
Compare the candidates
Play or sing the melody and chords against the suggested keys. Try another section and check the tonic and whether the music sounds major, minor or something else.
What the result means
How does this song key finder work?
The analyzer estimates pitch-class energy in one channel, then compares its overall pattern with statistical profiles for twelve major and twelve minor keys. It ranks three candidates for the selected section. The ordering is not a probability or a guarantee that the first candidate is correct.
Enharmonic names such as C♯ and D♭ can describe the same pitch in equal temperament; the notation that makes musical sense depends on the song. The analyzer assumes A4 = 440 Hz and does not determine the appropriate written spelling.
A song can change key, use modal or chromatic notes, have an ambiguous tonal center, or contain little pitched material. Relative major and minor keys share notes, so the same pitch collection can support more than one interpretation. Compare the melody, chords and sense of resolution, and listen to the actual section rather than relying on a label alone. The key-identification guide discusses checking a candidate key.
When a result is uncertain
Why might a key estimate be wrong?
Drums, noise, heavy effects, unusual tuning, very short melodies and different sections can mislead a pitch-class estimate. Silence or some noise-only sections are rejected, but other nonmusical or ambiguous sounds can still produce a candidate. Analyze a different section, compare the ranked alternatives and verify them with an instrument or a trusted score.
For stereo files this tool analyzes the louder channel in the chosen section instead of averaging channels that could cancel. It does not identify the song, detect chords or BPM, find individual notes, transpose audio or provide a professional music-theory assessment. For an estimated pulse, use the separate song BPM finder.
After verifying an original and target key, the pitch changer can prepare a semitone-shifted short-file copy. It changes every sound in the selected file and can introduce artifacts; listen to the result.
Analysis uses the MIT-licensed @audio/mir-chroma and @audio/mir-key packages and fourier-transform. License notices: audio/mir and fourier-transform. The tool code is downloaded, but selected audio is not uploaded.
A few useful answers
Free song key finder questions
How do I find the key of a song?
Choose a supported MP3 or WAV and enter the start of a musical section with chords and melody. Analyze up to 30 seconds, then compare the ranked candidate keys with the melody, chords and sense of resolution. At least eight seconds must remain.
Is the detected key always correct?
No. The tool compares the section’s pitch-class pattern with major and minor key profiles. Modulations, modes, unusual tuning, percussion and ambiguous harmony can give a misleading result or no result. Try other sections and verify by ear.
Why are major and minor both suggested?
Relative major and minor keys share a set of notes, so pitch content alone may be ambiguous. Listen for the tonal center and compare chords and melody; ranked candidates are not probabilities.
Is the audio uploaded?
No. The browser decodes and analyzes the chosen file locally. The tool does not identify the recording or save it for later.
Does it also find BPM or chords?
No. This tool estimates candidate major and minor keys for one section; it does not identify the song, BPM, chord progression or individual notes. Use the separate BPM finder for a tempo estimate.
What files are supported?
Supported mono or stereo MP3 and WAV files up to 50 MiB and five minutes. Browser codec support varies. At least eight seconds must remain at the chosen start time; at most 30 seconds of one channel are analyzed.
After preparing your audio