MP3 to MIDI for Piano

Updated 26 September 2026 · 8 min read

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 about other instruments?

Piano is the easiest case, not the only one. What actually decides the outcome is how close the source is to one pitched note at a time, because that is the assumption baked into the pitch tracker. Every instrument below is judged by that one rule. Where a number appears, it comes from running this build against its own test audio. It describes the converter on material like that, not a promise about your recording.

Can you convert guitar audio to MIDI?

Yes, but guitar asks more of the converter than piano does, for two specific reasons: the notes ring, and bends move the pitch while the note is still sounding. Melody mode tracks one pitch at a time and glues together the slices that agree; a sustained guitar note hands it a long decaying tail that is easy to split into two notes, and a bend reads as a slide through several pitches instead of one. Clean single-note playing converts best. Heavily distorted rhythm guitar is the worst case, because distortion adds harmonics that compete with the fundamental the tracker is looking for. Two settings do most of the work: narrow the note range to the span the guitar really plays, about E2 to E6 in standard tuning and lower if the part is detuned, so octave errors have less room; and raise Min note length to 80 ms or 150 ms so ringing tails stay one note. Run 30 seconds first. The conversion happens in your browser with no upload and no sign-up, so a test pass costs nothing.

Can you convert vocals to MIDI?

Yes. A solo vocal is the second-best source after piano, because it is one line at a time, which is exactly what melody mode is built for. Two things break it: vibrato and slides. Both move the fundamental while a note sustains, and the tracker writes that movement as a run of short notes rather than one; raising Min note length to 150 ms merges them back. On this build's own test audio, vibrato left every pitch correct but shifted the first note's onset by a few hundred milliseconds, the same mechanism, and it is a timing error you fix in a DAW rather than a wrong note. The other requirement is isolation: on a full mix the tracker follows the bass line instead of the melody, which is what we measured directly, so convert a lead vocal stem rather than the finished song. There is no account, no upload and no watermark on the output.

Can you convert a bass line to MIDI?

Yes. Bass is the easiest source after piano, for the opposite reason: a bass line is usually one note at a time, has a strong low fundamental and starts with a clear attack. The catch is octave slips. At the low end the tracker can land an octave above the real note, so narrow the range to what the instrument actually plays, roughly E1 to G3 on a four-string bass, instead of leaving the full A0 to C8 open. Bass also explains a failure you may already have seen: on this build's own test audio, a full mix with piano on top came out following the bass line instead of the melody. If your mix conversion looks like a root-note skeleton, that is what happened. Convert the bass stem on its own and keep it, rather than fighting the full mix.

Can you convert MP3 drums to MIDI?

Only partly, and drums are the weakest fit on this page. Most of a kit is noise rather than pitched sound: a kick, a snare and a hi-hat have no stable fundamental, so there is no pitch to track and nothing to turn into a note. Tuned material can come through (toms, a pitched kick, tuned percussion) while cymbals will not. Note also that drums to MIDI usually means something this tool does not do: mapping each hit to a fixed drum note, which is what General MIDI does with drum sounds rather than pitches, is onset detection, not pitch tracking. If you need a playable drum part from a drum recording, that is a drum-trigger or drum-replacement job; Ableton Live's own audio-to-MIDI conversion ships a separate Drums command for exactly that case, which we verified against Ableton's manual, and this page does not do it. Honest scope: this converter is built for pitched, single-line material.

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.

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

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.

How to convert MP3 to piano sheet music?

Two steps, and it helps to know which tool does which. This converter only does the first one: it turns the audio into a standard MIDI file, SMF format 1 at 480 ticks per quarter note with the tempo you set written into it, in your own browser with no upload and no sign-up. It does not draw staves. For the second step, import that MIDI into a notation program: MuseScore imports .mid files and converts them into notation, and its MIDI import panel exposes quantisation, maximum voices and a Split staff option that assigns a piano track to left and right hands, all documented in the MuseScore handbook. Quantise here first if you know the real BPM, because an unquantised MIDI turns into notation full of odd rests and ties. Then expect cleanup: MIDI carries no key signature and no enharmonic spelling, so you will be telling the program which sharps and flats you meant.

How to convert MP3 to piano notes?

Run the file and you get notes: pitch, start time, length and a velocity derived from how loud each one was. Not an audio file, not a picture of a piano roll. In practice, choose Melody mode, narrow the note range to C3 to C6 for a right-hand line, leave Min note length at 80 ms unless the passage is fast, and analyse 30 seconds before committing to the whole recording. On this build's own test audio, a clean piano source came back with 7 to 8 out of 8 notes at the correct pitch, which describes our test material rather than promising the same on yours. The result is a .mid file at 480 tpqn that opens in Ableton, FL Studio, Logic, GarageBand and MuseScore, with every note still editable. If what you wanted was staff notation rather than a piano roll, see the sheet music question above.