Music production
Producers write and edit parts as MIDI and choose the sound at the end. A DAW plays the same .mid file through any virtual instrument.
What Is a MIDI File? A Plain-English Guide to .mid Files
What is a MIDI file? It is a small file, usually ending in .mid, that stores music as instructions instead of sound: which notes to play, when each one starts and stops, how hard it is played and which instrument should play it. A synthesizer, app or DAW turns those instructions into audio, which is why a .mid file is tiny, fully editable and sounds a little different on every device. Drop any .mid file on the inspector below to see what is inside it, in plain English.
- Plain-English Answers
- Free .mid File Inspector
- Nothing Uploaded
- Facts Checked November 2026
Drop a MIDI file to see what is inside
.MID · .MIDI · .KAR · .RMIup to 10 MB each, nothing uploaded
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Reads Standard MIDI Files (type 0, 1 and 2) up to 10 MB and lists their header, tracks, tempo map, signatures and events. It only reads; to change a file, open it in the MIDI editor.
What Is a MIDI File? The Short Answer
MIDI stands for Musical Instrument Digital Interface, a standard first published in 1983 (midi.org) so that keyboards, computers and drum machines from different makers could talk to each other. A MIDI file, properly a Standard MIDI File, saves that conversation so another program can replay it later. Think of it as sheet music for machines: it says play middle C now, this hard, for this long, on a piano, but it holds no recording of a piano. Notes, not sound: that is the whole idea. It is also why the files are so small. The 26 second piano recording in our example weighs 356 KB as an MP3; the .mid file made from it is 1.3 KB. Have a recording and want the notes? Our free audio to MIDI converter can turn a recording into a MIDI file in seconds.
Inspect a MIDI FileMIDI vs MP3: How a .mid File Differs From Audio
MIDI and MP3 can both end up as music in your headphones, but they store completely different things. WAV is here for reference; audio sizes are worked out for a three-minute stereo song.
| MIDI (.mid) | MP3 | WAV | |
|---|---|---|---|
| What it stores | Note instructions: pitch, timing, length, velocity, instrument | Recorded sound, compressed | Recorded sound, uncompressed |
| Size of a 3-minute song | Set by the number of notes, not the length: a few KB to a few hundred KB | About 2.9 MB at 128 kbps | About 31.8 MB at CD quality |
| Sounds identical on every device | No | Yes | Yes |
| Holds vocals and real recordings | No | Yes | Yes |
| Edit a single note | Yes | No | No |
| Swap the instrument afterwards | Yes | No | No |
| Change tempo without changing pitch | Yes, instantly and losslessly | Needs time-stretching | Needs time-stretching |
| Opens in | DAWs, notation apps and any .mid file player | Any media player | Any media player or DAW |
Does a .mid File Contain Sound?
No. A .mid file contains no audio at all, only the instructions for it, so the sound you hear comes from whatever plays the file. Open the same file in a phone app, a DAW and a hardware keyboard and you hear three different pianos playing identical notes. To keep that predictable, the General MIDI standard gives every instrument a fixed number, 128 in all from Acoustic Grand Piano to Gunshot, and reserves channel 10 for drums, so a file that asks for a violin gets some kind of violin everywhere. How good that violin sounds is up to the player. It is also why MIDI to MP3 conversion exists: rendering fixes one performance into an audio file that sounds the same for everyone.
Open a .mid FileWhat Is Inside a .mid File, Part by Part
Every Standard MIDI File is built the same way: one header, then one or more tracks full of timed events. The inspector at the top of this page labels each part as it reads your file.
The header: format, tracks and timing
A .mid file starts with the four letters MThd, followed by three numbers: the format (0, 1 or 2), how many tracks follow and the timing resolution in ticks per quarter note. At 480 ticks, each beat is split into 480 steps, fine enough to keep every nuance of a human performance. The whole header is 14 bytes.
Read Your HeaderTracks: lists of timed events
After the header, a .mid file holds its track chunks, each marked MTrk. A track is a list of events, and each event waits a number of ticks after the one before it, a gap called delta time. Nothing in the file says which bar a note is in; positions come from adding the gaps up, and bars come from the tempo and time signature.
Inspect the TracksNotes: number, velocity and channel
A note is two events, note on and note off. Each carries a note number from 0 to 127, where 60 is middle C and each step is one semitone; a velocity from 1 to 127 for how hard it is played; and a channel from 1 to 16 that says which instrument plays it. A note lasts exactly as long as the gap between its on and its off.
Look at the NotesTempo, time signature, key and words
Meta events carry everything that is not a note: the tempo, stored as microseconds per beat (500,000 means 120 BPM), the time signature, the key signature, track names, lyrics and markers. A file with no tempo event plays at 120 BPM.
Read the TempoInstruments and controllers
A program change picks the instrument for a channel by its General MIDI number, and controller messages shape the sound while it plays: sustain pedal, volume, pan and modulation. Pitch bend slides a note up or down, the way a guitarist bends a string.
See the InstrumentsA Real .mid File, Byte by Byte
A complete two-track .mid file holding the opening of Twinkle, Twinkle, Little Star: the same parts the inspector above finds in your own file.
What you are looking at
The whole file is 145 bytes. The first 14 are the header: MThd, a length of 6, format 1, two tracks and 480 ticks per quarter note. The first track sets 100 BPM, 4/4 and C major. The second names the part Piano, chooses Acoustic Grand Piano and plays seven notes, each one 9 bytes: a note on, a delta time and a note off. Two bars of music in less space than this paragraph.
What Are MIDI Files Used For?
Because the notes in a .mid file stay editable, MIDI turns up anywhere music has to change after it is written.
Learning an instrument
Falling-notes apps and our MIDI player turn a .mid into a lesson you can slow down, loop and transpose.
Composing and notation
Notation apps such as MuseScore Studio import and export MIDI, and MIDI to sheet music turns a file into a printable score.
Backing tracks and karaoke
Singers move a backing track into their key in a second. Karaoke files ending in .kar are MIDI files with the lyrics added.
Games and virtual pianos
Many 1990s PC games shipped their soundtracks as MIDI because it was so small. Today .mid files still feed game audio tools and virtual pianos, as in MIDI to Roblox piano.
Moving music between apps
MIDI is the one format every DAW, notation app and keyboard understands, so a part can travel from one program to another without losing a note.
How to Open a .mid File on Any Device
After "what is a MIDI file?", how to open one is the question people ask most. Pick the line for your device.
Drop it on our free MIDI player to hear it with a piano roll and falling notes, or on the inspector above to see what it contains. Nothing to install, on any computer.
Install VLC, download a SoundFont (.sf2) and select it under Preferences, All, Input/Codecs, Audio codecs, FluidSynth. MuseScore Studio, which is free, opens .mid files as sheet music.
Drag the file from the Finder onto a software instrument track in GarageBand, free on the App Store, then choose the instrument that plays it in the Library.
Import the file into GarageBand from the Files app. Each MIDI track becomes a Keyboard track, up to 32 of them.
FL Studio, Ableton Live, Logic Pro, Cubase, REAPER and MuseScore Studio all import .mid files, ready to edit and voice with their own instruments.
Step 1 · In any browser
How to Make a .mid File: Five Ways
You do not need to play an instrument. Start from whatever you already have.
Convert a recording
Drop a song, a stem or a voice memo on the audio to MIDI converter on our homepage, or use MP3 to MIDI, voice to MIDI or piano to MIDI for a specific source. A model listens and writes the notes down.
Draw the notes
Open the free MIDI editor, start an empty song and click notes onto the piano roll, then export a .mid file.
Play a MIDI keyboard
Plug a MIDI keyboard into a DAW such as GarageBand, Logic Pro or REAPER, record a part and export it as a .mid file.
Start from sheet music
Write the music in MuseScore Studio and export MIDI, or convert an existing score with MusicXML to MIDI or sheet music to MIDI.
Generate the chords
Pick a key and a feel in the chord progression generator and download the chords as a .mid to build a song on.
Is a .mid File the Same as .midi? Types 0, 1 and 2
Yes: .mid and .midi are two spellings of the same Standard MIDI File, and any program that opens one opens the other. Karaoke files ending in .kar are MIDI too, with lyrics added (Library of Congress). The difference that does matter is the file type. A Type 0 file squeezes every part into a single track, the simplest form and the one some keyboards and phones expect. A Type 1 file keeps each part on its own track, which is what DAWs write and what you want for editing. Type 2, for separate patterns, was defined in the standard but never really caught on. The inspector above tells you which type your file is.
Check Your File TypeAre MIDI Files Legal? Where to Get a .mid File
The format is perfectly legal. What matters is the music inside it, which copyright can protect like any other copy of a song. This is general information, not legal advice.
The format is always legal
Making, opening, editing and sharing MIDI files is legal in itself. The only question is who owns the song in the file, and whether you may copy or share it.
Make your own
A MIDI file you make yourself, from your own song or a recording you have the right to use, is the safest source. Converting a recording is the usual way to get a MIDI file of a specific song.
Public domain libraries
Older compositions are often in the public domain. The Mutopia Project lists 2,124 pieces with MIDI files, each in the public domain or under a Creative Commons license (count as of November 2026).
Licensed MIDI files
Publishers and music stores sell MIDI files of popular songs with a license to use them. Free sites that offer any hit as a .mid file usually have no such license, so we do not link to them.
What Is a MIDI File? FAQ
Short, sourced answers, including the questions people ask ChatGPT about MIDI.
What is a MIDI file in simple terms?
A file of instructions for playing music: which notes, when, how long, how hard and on which instrument. It contains no recorded sound, so it needs a synthesizer, an app or a DAW to be heard.
What does MIDI stand for?
Musical Instrument Digital Interface. The MIDI 1.0 standard was first published in 1983, and Standard MIDI Files came a few years later so songs could move between programs. Both are published by the MIDI Association at midi.org.
Does a MIDI file contain sound?
No. It holds note events, tempo, instrument numbers and similar data, never audio. That is why one file sounds different from player to player, and why it is so much smaller than an MP3.
Are .mid and .midi files the same?
Yes. They are two extensions for the same Standard MIDI File format. Rename one to the other and nothing changes.
What are MIDI files used for?
Making and editing music in a DAW, learning songs with falling notes, printing sheet music, karaoke and backing tracks, game music, and moving a part between apps without losing a single note.
How can I open a MIDI file?
In a browser, drop it on our free MIDI player. On Windows, use VLC with a SoundFont or MuseScore Studio; on a Mac, iPhone or iPad, import it into GarageBand. Every DAW opens .mid files too. The step-by-step list above covers each device.
What is a .mid file player?
Any app that plays MIDI files through a synthesizer: the free MIDI player on this site, VLC with a SoundFont, GarageBand, MuseScore Studio, a DAW or a piano learning app. A plain audio player that has no synthesizer cannot play them.
Can VLC play MIDI files?
Yes, once you give it a SoundFont (.sf2). Select the file in Preferences under Input/Codecs, Audio codecs, FluidSynth. According to VideoLAN's wiki, Windows builds lacked MIDI support from version 2.1.0 until 3.0.0, so use a current version.
Can ChatGPT make a MIDI file?
Partly. ChatGPT can write the notes of a short melody or chord progression as text or code, and with its code tool it can often save that as a small .mid file to download. It cannot hear your audio or a song you name, so it cannot transcribe a recording, and longer pieces often come out wrong. To turn real music into MIDI, use a converter such as MP3 to MIDI; to fix what ChatGPT wrote, open it in the MIDI editor.
Are MIDI files legal?
The format is. A MIDI file of a song is a copy of that composition, so sharing or downloading MIDI versions of copyrighted songs without permission can infringe, while your own music and public domain works are fine. When in doubt, make the file yourself for personal practice or use a licensed source.
Where can I get MIDI files of songs?
Make them from recordings you have the right to use, download public domain and Creative Commons pieces from libraries such as the Mutopia Project, or buy licensed MIDI files from publishers. Avoid sites that hand out copyrighted hits with no license.
How do I get a MIDI file of any song?
Convert a recording of it. Drop the song, or better an isolated stem, on MP3 to MIDI, check the result and download the .mid. A single instrument gives a clean result; a full band mix gives a rough sketch with every part in one track. Keep it for personal use unless you hold the rights.
How to get MIDI files for free?
Three free, legal routes: convert a recording you own, draw the notes in the free MIDI editor, or download from public domain libraries. All three give you a standard .mid file that every app can open.
Can I convert a MIDI file to MP3?
Yes. MIDI to MP3 renders the notes to an audio file anyone can play, and MIDI to WAV gives a lossless copy for a DAW. Because the file has no sound of its own, the result depends on the instruments that do the rendering.
Why is a MIDI file so small?
Because it stores events, not sound waves. In the byte-by-byte example above, a whole note takes 9 bytes, while one second of CD-quality audio takes about 176,000. Length barely matters; the number of notes does.
What files can be converted to MIDI?
Audio such as MP3, WAV, M4A, FLAC, OGG and AAC through our converters, the soundtrack of a video through MP4 to MIDI, MusicXML through MusicXML to MIDI, and printed or PDF scores through PDF to MIDI.
Free Tools for Every .mid File
Make a .mid File From What You Have
A song, a voice, a score or a chord idea: each one can become a MIDI file.
- Audio to MIDI ConverterTurn any recording into an editable MIDI file.
- MP3 to MIDI ConverterConvert MP3 songs and stems to MIDI.
- Voice to MIDIHum, sing or whistle a melody into notes.
- Piano Audio to MIDITranscribe piano recordings into MIDI.
- MusicXML to MIDI ConverterConvert MusicXML files to MIDI.
- Chord Progression GeneratorBuild progressions and export MIDI.
What Is a MIDI File? Open One and See
Drop any .mid file on the inspector at the top of this page to see its header, tracks, notes and tempo in plain English. It is free and nothing is uploaded.