Is It Legal to Convert a Copyrighted Song to MIDI?
Last updated 4 October 2026
Short answer: transcribing a song for your own private study, practice or analysis is a different act from publishing the result. The transcription is a derivative of the song's composition, so the composition's rights still apply to it — but the step that most commonly turns a private act into a problem is distribution: posting the .mid to a public sheet-music or MIDI site, adding it to a sample pack, selling it, or performing it in public. We are not lawyers and nothing here is legal advice. What we can do is state, with measurements rather than claims, what this tool does and does not do: the audio never leaves your device (0 bytes uploaded), no account is created, and the file you receive is a 432-byte set of note instructions containing zero bytes of audio.
The three things people lump into one word
"Convert a song to MIDI" sounds like a single action. Legally it is usually three, and they are not treated the same way:
- Making a copy. Decoding the audio and writing a new file is a reproduction — even when the new file is much smaller than the original.
- Making a derivative work. A MIDI transcription of the melody, harmony and rhythm is derived from the song's composition, which is a separate right from the recording.
- Distributing or performing it. Publishing the result, sharing it, selling it, or playing it in public.
The first two happen on your own machine, in private, when you use a converter that runs locally. The third is a choice you make afterwards, and it is the one that most often decides whether a private act stays private. A converter cannot make that choice for you — but it can avoid making it for you, which is exactly what a tool that uploads your file is doing: it has already put a copy on someone else's server before you decided anything.
What this tool does — measured, not asserted
The rest of this page is a fact, and you can reproduce it. We loaded the converter, attached a network monitor to the tab, and converted a 20-second recording through the real file input while logging every request and the size of every request body. Then we took the resulting .mid apart byte by byte.
| What we did | What we measured |
|---|---|
| Source file | a 20-second WAV, 1,764,044 bytes |
| Conversion time | 27,569 ms |
| Notes detected | 40, spanning D4 to A4 |
| Output file | 432 bytes |
| Output as a share of the source | 0.0245% — about 1/4,083 |
| Bytes of audio inside the output | 0 |
| Data uploaded during the conversion | 0 bytes |
Here is the whole of that 432-byte file, event by event:
| Inside the 432 bytes | Count |
|---|---|
Header (MThd): format 0, one track, 480 ticks per quarter note | 1 |
Track chunk (MTrk), 410 bytes | 1 |
| Note-on events | 40 |
| Note-off events | 40 |
| Controller messages — the pitch-bend range setup | 4 |
| Meta events — track name, tempo, time signature, end of track | 4 |
| Pitch-bend events | 0 |
| System-exclusive events | 0 |
| Bytes of audio | 0 |
That is the entire file. The track name written into it is mp3 to midi. The 40 notes are stored as 40 pairs of note-on and note-off messages, each carrying a velocity of 90. There is no sample data, no waveform, no embedded recording, and no reference to the source file's name or location. At 432 bytes, the whole output is the same size as about 2.4 milliseconds of CD-quality audio — 176,400 bytes per second of stereo 16-bit sound.
On the network side, the log is just as short. During the conversion there was exactly one request and 0 bytes uploaded; across the whole session the total uploaded request body was 0 bytes. The only non-GET request in the entire run was this site's own analytics beacon, which carries an empty body and nothing derived from the audio. There is no upload endpoint, no account, no server-side copy and no sharing feature — which means there is nothing for us to retain, and nothing we could publish even if we wanted to.
What the size difference does — and does not — mean
It is tempting to read "432 bytes, no audio inside" as "therefore no copyright issue". That is the wrong conclusion, and it is worth being precise about why.
Copyright in a song is usually split into at least two rights: the composition (the notes, melody, harmony, and any lyrics) and the sound recording (that particular performance, in that particular studio, on that particular day). The measurements above show that the output contains no part of the recording — so it is not a copy of that recording. But the note events it encodes are still derived from the composition. A transcription is therefore a derivative work of the composition, and the composition's rights do not disappear because the file is small.
The size of the file changes what kind of thing you have. It does not change whose rights are involved. That distinction is the whole reason the next section exists.
The risk ladder: what you do with the file
Most people who ask this question are really asking "where is the line?" The line is not "free versus paid". It is closer to "private versus public". Read this as the general shape of how people approach it, not as a rule you can rely on in your own country:
| What you do with it | What that typically involves | Why the risk moves |
|---|---|---|
| Learn the chords for yourself | Private, on your own device; no copy leaves it | Closest to private study |
| Practise along, or analyse the structure | Private study of a work you have a copy of | Commonly treated as permitted in many places |
| Transcribe your own performance | Your own playing, from your own recording | No third-party right is involved |
| Keep it on your own drive | Still private; nothing is published | The decision to distribute has not been made |
| Use it in a lesson you teach | Teaching exceptions exist, but are narrower than people assume | Depends heavily on jurisdiction and setting |
| Share it with a bandmate or a class | A limited circle, but still a copy going to someone else | Starts to look like distribution |
| Post the .mid on a public sheet-music or MIDI site | Distribution to the public, whether or not you are paid | This is where it usually changes |
| Upload it to a sample pack or stock library | Commercial distribution | Someone else may now exploit it |
| Sell it, or use it in a released track | Commercial exploitation of a derivative work | Direct commercial use |
| Perform or stream it in public | A separate public-performance right applies | A different right from copying |
| Publish it and credit the original artist | Credit is not permission | Attribution does not create a licence |
This ladder is a description of how these situations are commonly discussed, not a legal test, and it is not legal advice. The only reliable answer for your own situation comes from a qualified professional in your jurisdiction.
Where people go wrong
- "I bought the MP3, so I own the song." You bought a licence to listen to that recording. The composition is a separate right and was not part of the sale.
- "I credited the artist, so it's fine." Credit is courtesy. Permission is a licence. They are not interchangeable.
- "It's not for money, so it's allowed." Distribution does not require payment. Posting a file publicly is distribution whether you charge for it or not.
- "The song is old, so it's public domain." The composition and the recording have separate terms. An old composition captured in a recent recording is not automatically free.
- "The converter did it, so it's the converter's problem." The tool is neutral about rights; what matters is what you do with the output.
- "It's for school, so it's exempt." Teaching exceptions exist in many places but are narrower than people assume, and they vary by country.
- "It's on a streaming service, so it's free to reuse." Availability is not a licence.
- "Only the recording is protected." The composition is protected separately, and for a transcription it is usually the more relevant right of the two.
Habits that keep a private transcription private
- Keep the derived work on your own device by default. The measurements above are the reason this is easy here: converting uploads nothing, so nothing exists to leak or to be published by accident.
- Do not upload a transcription of someone else's song to a public repository, a sheet-music site, or a sample pack. That single step is what moves a private act onto the riskier rungs of the ladder.
- When you want to publish, start from material you can publish. Your own compositions, material that is genuinely public domain in both the composition and the recording, or material you have a licence for.
- Treat credit as a courtesy, not a permission. If you need permission, get a licence.
- Ask locally. Copyright is territorial, and the practical answer for a specific use depends on where you are and what you intend to do with it.
What the file it writes actually is
None of the above changes what the writer produces, so here it is in full — the same in every conversion:
| Format | Standard MIDI File, format 0 — one track, every note in it |
| Resolution | 480 ticks per quarter note |
| Tempo | Measured from the note onsets and written into the file; 500,000 µs per quarter note (120 BPM) only when no steady pulse can be found |
| Time signature | 4/4, a constant |
| Track name | mp3 to midi |
| Pitch-bend range | ±2 semitones, set explicitly with an RPN 0 message, centre 8192 |
| Velocity | clamp(amplitude × 127, 1, 127), carried from the model's own confidence value rather than measured from the audio |
| Note-off velocity | Fixed at 0x40 (64) on every note |
| Shortest note | 0.02 s — anything shorter is clamped up to it |
| Audio content | None. The file carries note events only — 0 bytes of samples |
Everything on this page happens inside your browser tab. The audio is decoded, down-mixed to mono and resampled before a transcription model running on your own machine turns it into note events. Nothing is sent anywhere, which is why the upload total above is zero — and why the only person who can decide to distribute the result is you.
Frequently asked questions
Is it illegal to convert a song I bought to MIDI?
Buying a copy of a recording normally buys you a licence to listen to that recording, not ownership of the song's composition. Converting it for your own private study or practice is, in many places, treated differently from publishing the result. The activity that most reliably changes the picture is distribution — posting the .mid publicly, selling it, or performing it in public. This is general information, not legal advice, and the rules differ by country.
Does the MIDI file contain a copy of the original recording?
No, and we measured it rather than asserting it. A 20-second recording of 1,764,044 bytes converted into a 432-byte .mid — about 1/4,083 of the source, roughly the size of 2.4 milliseconds of CD-quality audio. Taken apart, those 432 bytes contain 40 note-on and 40 note-off events, four controller messages, four meta events and zero bytes of audio: no samples, no waveform, and no reference to the source file. The notes it encodes are still derived from the composition, so it remains a derivative work — the file being small changes what kind of thing it is, not whether the composition has rights.
Does converting a song upload it to a server?
Not with this tool. We attached a network monitor to the tab during a real conversion: during the conversion itself there was exactly one request and 0 bytes uploaded, and across the whole session the total uploaded request body was 0 bytes. The only non-GET request in the entire run was this site's own analytics beacon, which carries an empty body. There is no upload endpoint, no account, no server-side copy and no sharing feature — which means no copy of your audio exists anywhere but your own machine.
Is it legal to convert a song to MIDI if I never sell it?
Not selling it helps, but it is not the dividing line people assume. Distribution does not require payment: posting a transcription to a public sheet-music or MIDI site, putting it in a shared drive, or playing it in public can all be distribution regardless of money. Keeping the result private on your own device is the version that stays closest to private study. This is general information, not legal advice.
Can I post the MIDI I made to a sheet-music site?
That is the step that usually changes the analysis, because publishing it makes the transcription available to the public. A tool that runs locally leaves that decision entirely to you — nothing is uploaded when you convert, so nothing is published unless you choose to publish it. If you want to publish a transcription, the safe route is material you wrote yourself, material that is genuinely public domain in both the composition and the recording, or material you have a licence for.
Does crediting the artist make a transcription legal?
No. Credit is courtesy; permission is a licence. Attributing the original songwriter does not grant you the right to distribute a derivative of their composition. This is one of the most common misunderstandings around transcriptions, and it is worth separating the two ideas clearly: giving credit does not create a right that was not there.
Is public domain music always safe to convert and publish?
No, because a song usually carries at least two separate rights with separate terms: the composition and the sound recording. An old composition can be in the public domain while a recent recording of it is still protected. Before you publish a transcription, check that both the composition and the particular recording you worked from are free in your country — or that you recorded the performance yourself.
Related: what leaves your device when you convert, what happens when you convert public-domain recordings, and why the converted file opens at the wrong tempo.