MP3 to MIDI for Piano
Short answer
Yes — solo piano is the easiest source you can hand an MP3 to MIDI converter. On a clean piano recording this converter recovers 7 to 8 out of every 8 notes at the correct pitch. Piano wins for a structural reason, not a marketing one: melody mode tracks one pitch at a time, and a piano melody usually is one note at a time. The settings that matter most are note range and minimum note length; the failure you should expect is dense two-handed material, not the instrument itself.
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Why piano converts better than almost anything else
Every MP3 to MIDI converter, this one included, has to guess which note is sounding from a waveform. The reliable way to do that is to look at one short slice of audio at a time and ask how periodic it is — periodicity is what separates a musical note from noise. This page uses the YIN autocorrelation method for that, and then glues consecutive slices that agree on the same pitch into a single note.
That design has one assumption baked into it: one note sounds at a time. Piano is the instrument that most often satisfies it. A right-hand melody line, a flute part, a vocal take — all single-line sources. A finished mix is not, which is exactly why a whole song converts badly on every converter on the market.
Piano has three more things going for it that have nothing to do with the algorithm:
- Clean attack. A hammer hitting a string gives the pitch tracker an unambiguous onset to lock onto.
- Strong fundamental. The pitch tracker is looking for the fundamental frequency; a piano puts real energy there rather than mostly in the overtones.
- Fast decay. Notes end cleanly, so one note does not bleed into the next the way a sustained pad or a bowed string does.
What the conversion actually produces, measured
Numbers below come from running this build against its own test audio — a C major scale, C4 D4 E4 F4 G4 A4 B4 C5, played as a clean piano-like tone with the ground truth known. These describe the converter on the kind of audio it is built for. They are not a promise about how it behaves on your specific recording.
| Piano source | What came out |
|---|---|
| Clean piano recording | 7–8 of 8 notes at the correct pitch |
| Piano with vibrato | Correct pitches; the first note's onset can shift by a few hundred milliseconds |
| Piano with reverb | Correct pitches, but a sustained note sometimes splits into two |
| Piano with heavy background noise | All 8 notes present and in order, plus a few false low notes in the gaps |
| Full mix with piano on top | Reader follows the bass instead of the melody |
The pattern is consistent: pitch is usually right, timing and note count are what degrade. That is the opposite of what most people expect, and it tells you which knob to reach for.
Where piano breaks — and what to do about it
Two hands at once
Melody mode cannot hear two lines. When a left-hand part is playing under the melody, the tracker follows the louder or more periodic of the two and the other line disappears. If you have stems, convert them separately. If you do not, you can try Chords mode, which reads spectral peaks instead of a single fundamental — it is experimental, it works best on sustained material, and it will miss notes in anything dense.
Sustain pedal
A held pedal lets earlier notes ring under later ones, which is effectively two or three notes at once. Romantic and impressionist repertoire lives here, and it is the single biggest reason a piano MP3 converts poorly. Shortening the analysed section to a passage with less pedal, or picking a section where the pedal lifts between phrases, gets you markedly further than any setting change.
Reverb and room tail
Reverb glues the end of one note to the start of the next, so a sustained note gets written as two shorter ones. If your source is a live room recording, trim long tails before converting, or raise Min note length so the split fragments merge back into one note.
Arpeggios and fast runs
Notes shorter than the analysis window get missed or merged. Lowering Min note length to 40 ms keeps fast passages, at the cost of letting more false notes through in quiet sections.
The setting that fixes most bad piano conversions: note range
This is the highest-leverage control on the page and the one people skip. The converter will happily search A0 to C8 — 88 keys — for every slice of audio. A right-hand melody occupies a fraction of that, and every octave you leave open is another chance for the pitch tracker to land on the right note in the wrong octave. Octave errors are the most common complaint about audio to MIDI conversion, and narrowing the range removes most of them before they happen.
Settings that work for piano
| Setting | For a piano melody | Why |
|---|---|---|
| Mode | Melody | Piano lines are single-note; this is the mode built for it |
| Note range | C3 to C6 for a right-hand line | Cuts most octave errors before they happen |
| Min note length | 80 ms normally, 40 ms for fast runs | Short notes get merged above this threshold |
| Sensitivity | Start at 6; lower if false notes appear | Quiet pedal hiss and room noise read as notes when set high |
| Quantize | Off unless you know the real BPM | Quantising to the wrong tempo makes good timing worse |
| Analyse | 30–60 s first, then the whole file | Find settings that work before committing to a long run |
What you get at the end
A .mid file, standard MIDI, SMF format 1 at 480 ticks per quarter note, with the tempo you set written into it. Every detected note keeps its pitch, start time, length and a velocity derived from how loud it was — so nothing is baked in and everything is editable. It opens directly in Ableton, FL Studio, Logic, GarageBand and MuseScore.
If you want staff notation rather than a piano roll, import the MIDI into MuseScore or any notation program. Do not expect the notation to be engraved correctly on the first pass: MIDI has no concept of enharmonic spelling, so you will be telling it which sharps and flats you meant.
FAQ
Can I convert a piano MP3 to MIDI for free?
Yes. No account, no upload, no cap on the number of files, and no watermark on the output. The file is decoded and analysed by your own browser.
Why does my piano conversion have extra notes in the quiet parts?
Once the real note has decayed, pedal hiss and room noise can still read as periodic signal and get written as a note, usually low in the range. Lower Sensitivity until the extras stop, or raise Min note length so short fragments are discarded.
Will it pick up the left hand as well as the right?
Not in a single pass. Melody mode follows one pitch at a time, so with both hands playing it locks onto the more prominent line and the other is lost. Convert separately if you have stems; otherwise use Chords mode for sustained material and accept that it will miss notes.
What note range should I use for piano?
Narrow it to what the part actually plays — most right-hand melodies sit inside C3 to C6. Leaving A0 to C8 open only gives the tracker more room to land an octave off.
Does classical piano convert well?
Single-line repertoire does; dense Romantic repertoire does not. A Bach invention will come out far cleaner than a Chopin nocturne, because several notes sounding at once defeats a one-note-at-a-time tracker.
Can I edit the MIDI afterwards?
Yes. It is a standard MIDI file at 480 ticks per quarter note with the tempo you set inside it. Open it in any DAW or notation program and every note stays editable.
Try it on your own piano file. Start with 30 seconds, set the range to C3–C6, and see what comes back before you run the whole recording.