MID to MIDI File Inspector
Inspect what is inside a .mid file, then re-export the parsed sequence with the full .midi extension — locally in your browser.
- Local processing
- Track & note counts
- .midi export
Click a note to hear it
MIDI file inspector
Parse and normalize locally
Drop a MID or MIDI file here, or browse
MID / MIDI · maximum 10 MB
How it works
Choose a MID file
Open a .mid or .midi file up to 10 MB. The file stays in the browser and is parsed locally.
Read the file summary
Check the number of tracks and notes, total duration, first tempo event, and detected General MIDI instruments.
Save as MIDI
Re-serialize the parsed sequence and download a normalized copy using the .midi extension.
Formats & limits
- Input formats
- MID
- Output
- MIDI
- File limits
- 50 MB · 10 min
- Price
- Free · no sign-up
What the inspector tells you
- .mid and .midi are extensions for the same Standard MIDI File format; renaming alone does not validate a damaged file.
- Track count includes empty or metadata-only tracks, while the note count sums playable note events.
- The displayed tempo is the first tempo event; a file may contain later tempo changes.
- Instrument names come from General MIDI program numbers and may differ from custom sounds in the original project.
- Re-exporting normalizes the header and event encoding, but the full tempo-change list (not just the first one) is already preserved in the file — the page just displays the first value.
Frequently asked questions
Are MID and MIDI different formats?
No — they are the same underlying format wearing two different filename extensions. Both .mid and .midi refer to the Standard MIDI File specification, and a file saved with one extension contains exactly the same kind of track, note, and timing data as one saved with the other; nothing about the internal structure changes based on which three or four letters follow the dot. The distinction exists mostly for historical reasons, since some older operating systems and software only recognized three-letter extensions, so .mid became common on those systems while .midi remained valid everywhere else. This tool exists partly because of that confusion — it lets you open either extension, inspect what's actually inside, and re-save it under the fuller .midi extension if that's what a particular workflow expects.
Does this tool upload my MIDI?
No — nothing about this page sends your file anywhere. Parsing, reading the track and note data, and re-exporting a normalized copy all happen locally inside your browser using JavaScript, with no server-side processing and no network request carrying your file's contents at any point in the process. This is different from the audio-transcription pages on this site, which do send uploaded audio to a backend for AI-based pitch detection — a MIDI file, by contrast, is small, already structured data that a browser can parse entirely on its own, so there's no technical reason to round-trip it through a server. If you're inspecting something you'd rather not upload anywhere at all, this is the one tool on the site built specifically around that constraint.
Does re-exporting change the music?
The musically meaningful content — parsed notes, their timing, velocities, tracks, and any other events the parser recognizes and supports — is read in and then serialized again into a fresh, normalized file, so the notes you hear should sound identical to the source. What can be lost in that round-trip is anything outside the standard MIDI note-event model: proprietary or application-specific metadata some DAWs embed in custom chunks, for instance, which this tool doesn't recognize and therefore can't preserve through a re-export. For a file that's purely about the notes, tempo, and instrumentation, this makes no audible difference at all; for a project file carrying extra DAW-specific state, treat the re-exported copy as a clean note-data version, not a full project backup.
Can it repair a corrupt MIDI file?
It can normalize and clean up any file that parses successfully in the first place — fixing inconsistent header encoding, non-standard event ordering, or other structural quirks that a strict MIDI reader elsewhere might reject, since the act of parsing and re-serializing naturally produces a well-formed file. What it cannot do is reconstruct a file whose MIDI structure is damaged badly enough that the parser can't make sense of it at all — a truncated download, a file with corrupted header bytes, or one that was never valid Standard MIDI to begin with will simply fail to load, with no editing tools here able to guess at what the missing or broken data was supposed to contain. If a file won't open, the safest next step is finding a fresh copy rather than trying to force this or any other tool to invent the missing structure.
Can I play the MIDI file here?
No — this page is built specifically for inspecting file structure and re-exporting a normalized copy, and deliberately doesn't include audio playback, since that would need a synthesizer and instrument sounds this simple, fully client-side tool doesn't carry. To actually hear the file, open the original or the re-exported copy in a DAW, a standalone MIDI player, or any notation app that supports playback — any of those will read the same Standard MIDI File data this tool parses and assign real instrument sounds to it. If you specifically want to render it into an audio file rather than just listen once, MIDI to MP3 on this site does exactly that, using a SoundFont voice you can choose, and produces a downloadable audio file instead of just playback.
Does re-exporting keep every tempo change, or just the first one shown?
The on-page summary panel intentionally shows only the first tempo event, purely to give you a quick, single-number read of roughly how fast the piece is without cluttering the display with every change — but that display choice has no effect on what actually gets written to disk. The file this tool produces when you re-export preserves the complete tempo map exactly as parsed from your source file, including any later tempo changes, ritardandos encoded as a series of tempo events, or multi-section pieces that speed up and slow down throughout. Nothing about the downloaded MIDI file is truncated to a single fixed tempo value; the simplification only ever happens in the summary statistics shown on screen, never in the file itself.