MIDI Editor
Open a .mid file, fix the notes on a piano roll, hear it, and export it again. No install, no account, and the file never leaves your browser.
Click to add a note, drag to move it, drag its right edge to lengthen it, press Delete to remove it. 0 notes.
What it does
A piano roll, without opening a DAW
Sometimes you need to change four notes in a MIDI file. Launching a full digital audio workstation, making a project, importing, editing, exporting and throwing the project away is an absurd amount of ceremony for that, and it is why standalone MIDI editors keep existing.
This is one that needs no install. Open a .mid and the notes appear on a piano roll: pitch up the vertical axis, time across the horizontal, bar lines every four beats. Click to add a note, drag to move it, drag its right edge to change its length, press Delete to remove it. Play it back to hear the result, then export a standard MIDI file that any DAW or notation program will open.
It edits notes and tempo, and that is the whole scope. Controller data, pitch bend, program changes and separate tracks are read but not editable, and they are not written back on export — a multi-track file comes in as one merged part and leaves as one track. That is a real limitation and worth knowing before you use this on something you care about, rather than discovering it afterwards.
How it works
How to edit a MIDI file online
Open, edit, export. Or start from nothing.
- 01
Open a .mid file, or just start clicking
An existing file loads its notes and its tempo onto the grid. With no file at all, the empty roll is a perfectly good place to sketch something from scratch.
- 02
Move the notes around
Click on empty space to add, drag a note to move it in time or pitch, drag its right edge to change its length. Everything snaps to sixteenths.
- 03
Play it, then export
Playback uses a simple synth tone so you can check the notes. The export is a normal standard MIDI file.
What you get
What an online MIDI editor needs to be usable
Direct editing, no modes to learn
Four gestures cover everything: click, drag, drag-the-edge, Delete. There is no pencil tool to select and no tool palette to get lost in.
A grid you can read
Four octaves from C2 to C6, black keys shaded, a heavier line on every bar. You can see where the beat is without counting pixels.
- pitch
- position
- length
- tempo
- controllers
- pitch bend
- program changes
- separate tracks
The natural second half of MP3 to MIDI
Audio-to-MIDI conversion always gets some notes wrong — a missed onset, an octave in the wrong place. Fixing those by hand is exactly what this is for, and the two tools are meant to be used in sequence.
A MIDI file editor with nothing to install
No download, no plugin, no account. Once the page has loaded it does not need the network at all, and your file is never transmitted anywhere.
Who uses it
What people come here to fix
Cleaning up a converted transcription
Audio-to-MIDI output is a good draft with a handful of wrong notes. This is where they get corrected.
Checking what is actually in a file
Before importing someone else’s MIDI, look at it. The piano roll answers in seconds what a DAW takes minutes to set up for.
Sketching a melody
An empty grid, a few clicks, a playback — quicker than opening a project for an idea that may not survive the afternoon.
Fixing one wrong note
The single most common reason anyone opens a MIDI editor, and the worst possible reason to launch a DAW.
Changing the tempo of a MIDI file
Move the tempo slider and export. The notes keep their musical positions; only the speed changes.
Teaching how a piano roll works
Nothing to install on a room full of machines, and nothing anyone can accidentally save over.
FAQ
MIDI editor questions
No, and this is the most important thing to know. Notes and tempo are preserved. Controller data, pitch bend, program changes and the division into separate tracks are not — a multi-track file is merged into one part when it loads, and exporting writes a single track. Keep your original file if any of that matters.
Not currently. Everything lands on one roll. If you need per-track editing, a DAW or a desktop editor is the right tool — this is built for the case where you want to change a few notes without that overhead.
A plain synthesised tone, deliberately. It exists so you can verify the notes are where you meant them, not to represent the final sound. Assigning a real instrument is a job for whatever you import the export into.
Notes snap to sixteenths when you move or resize them, and new notes are created as eighths. There is no free-position mode yet. Snapping is what makes mouse editing tolerable; without it nothing lands on the beat.
C2 to C6, four octaves. That covers melodies, bass lines and chord parts. Notes in a loaded file outside that range are not shown — another reason to keep the original.
That is one of the main reasons it exists. Audio-to-MIDI conversion is inherently imperfect — it misses quiet notes and occasionally puts one in the wrong octave. Convert with the MP3 to MIDI tool, open the result here, correct what is wrong, export.
Yes. It is a standard MIDI file — Ableton, Logic, FL Studio, Reaper, Cubase, GarageBand, MuseScore and anything else that reads .mid will import it normally.
No. It is parsed, edited and written back entirely in this page. Nothing is transmitted, which also means the editor keeps working if your connection drops.
Not yet, so be a little careful with Delete. The practical safeguard is that your original file is untouched — reopening it starts over.
Yes, with no account and no limit. It runs on your machine, so there is nothing to meter.
Edit a MIDI file
Open a .mid, move the notes, export it again. Nothing to install.