A free online MIDI editor with a real piano roll
This MIDI editor online gives you a piano roll in the browser: time runs from left to right, pitch from bottom to top, and every note is a bar you can draw, drag, stretch or delete. Write a melody, sketch chords and a bass line on separate tracks, give each track a General MIDI instrument, and play the whole arrangement back with sampled instruments. When it sounds right, download a standard .mid file for your DAW, notation program, game or keyboard.
You can also open an existing MIDI file to fix wrong notes, tidy timing with quantise, change instruments, transpose a part or remove a track — a quick MIDI file editor without installing anything. A short demo loop is loaded so you can press Play straight away, and your song is saved in this browser after every change, so an accidental tab close does not lose it.
How to use the MIDI Editor
- Press Play to hear the demo loop, or New song to start from an empty track (Undo brings the demo back).
- Set the tempo and time signature, choose the snap grid (1/16 by default) and the length for new notes.
- With Draw selected, click or tap the grid to add a note; drag sideways while adding to set its length. Drag a note to move it, drag its right edge to resize it, double-click or right-click it to delete it.
- Use Select to drag a box around several notes, then move, duplicate, quantise or delete them together, or change their velocity in the lane under the roll.
- Under Tracks, add a track for each part and choose its instrument or a drum kit; M mutes and S solos a track while you listen.
- Press Download .mid to save the song, or Open a .mid file to edit one you already have.
MIDI Editor features
Piano roll editing
Add, move, resize and delete notes with mouse, touch or keys; multi-select with a box or Shift; copy, paste and duplicate; Alt-drag copies.
Snap and quantise
Snap to bars, 1/2 to 1/32 notes or triplets, or edit freely; quantise starts and ends at 25–100 % strength.
Velocity lane
Each note’s velocity (1–127) is a bar under the roll — drag it to make notes louder or softer, or type a value for the selection.
Up to 16 tracks
Each track has its own name, General MIDI instrument or drum kit (channel 10), mute and solo.
Real instrument playback
Songs play through the same SoundFont synthesiser as the MIDI Player; load your own .sf2 to hear your sounds.
Undo, redo and autosave
Up to 200 steps of undo, and your song is stored in this browser after every edit.
Keyboard and touch editing
The roll is fully usable without a mouse. Click it or Tab to it, then use the arrow keys to move a dashed cursor and Enter to drop a note there, which lets you type in a melody note by note. With notes selected, the arrows move them by one grid step or one semitone, Shift with up or down moves an octave, and Shift with left or right shortens or lengthens them. The brackets step through notes one at a time, and the Note panel shows the exact pitch, bar, beat, length and velocity of the selected note as ordinary form fields you can type into.
On a phone or tablet, tap to add notes in Draw mode and drag them with one finger; scroll the roll with two fingers or switch to Scroll mode. The right-hand end of a note has a wider grab area on touch screens so resizing is easier.
What gets saved in the .mid file
Files are written as Standard MIDI File type 0 at 480 ticks per quarter note, which every DAW and notation program can read. Tracks are given MIDI channels 1–9 and 11–16 in order. If two notes of the same pitch overlap on one channel, the earlier one is ended where the later one starts, because MIDI cannot hold the same key twice.
| Saved | Details |
|---|---|
| Notes | Pitch, start, length and velocity of every note on every track |
| Tempo and metre | One tempo (20–300 BPM) and one time signature, at the start of the file |
| Instruments | A General MIDI program change per track; drum tracks use channel 10 |
| Song name | Written as the sequence name |
| Not saved | Mute and solo (they only affect playback), track names (a single-track type 0 file has no per-track names) |
Limits
- One tempo and one time signature per song. When you open a file with tempo changes, its notes keep their timing in seconds but are placed on a grid at the first tempo.
- Opening a file groups notes by MIDI channel into tracks; controllers, pitch bend, lyrics and per-track names are not kept.
- Sound needs the synthesiser and the 14.6 MB General MIDI sound set, downloaded once on the first Play. The editing beep works offline.
- Very large songs may not fit in browser storage; the page tells you if that happens, and you can still download the .mid file.
MIDI Editor FAQ
Is this MIDI editor free?
Yes. There is no sign-up, no watermark and no limit on the number of songs you make or download.
Can I edit an existing MIDI file online?
Yes. Press Open a .mid file (or drop the file on the roll). Each MIDI channel becomes a track you can edit, then download the result as a new .mid.
How do I quantise MIDI notes?
Choose a grid such as 1/16, select the notes (or none to use the whole track) and press Quantise or the Q key. Lower strengths move notes only part of the way, which keeps some human feel.
How do I change the instrument of a MIDI track?
Pick the track under Tracks and choose a General MIDI instrument in the Instrument list, or Drum kit for percussion.
Will I lose my work if I close the tab?
No. The song is saved in this browser after every change and reopened next time. Clearing site data removes it, so download the .mid file to keep a copy.
Does it work on a phone?
Yes. Tap to add notes, drag to move them and use two fingers to scroll. A larger screen is more comfortable for long songs.
Can I record from a MIDI keyboard?
Not into the piano roll. To play live, use the Online Piano or the Online Synthesizer, which accept a MIDI keyboard and can save a MIDI or audio take.