Free online SMF to MIDI converter

A sequencer, keyboard, notation program, or DAW may save a Standard MIDI File with .smf while another application accepts only .mid or .midi. Converting or renaming the file makes the sequence easier to import, edit, share, or load on hardware that expects a standard MIDI filename.

What the SMF format is

SMF means Standard MIDI File. It is a binary container for MIDI performance data, including notes, timing, tempo, time signatures, program changes, controller movements, pitch bends, track names, and other sequencing events. It contains no recorded audio.

DAWs, notation applications, MIDI editors, hardware sequencers, arranger keyboards, and sound modules create or use SMF files. The standard normally uses .mid or .midi; some music applications and devices use .smf for the same type of data. A valid Standard MIDI File begins with an MThd header and contains one or more MTrk track chunks.

SMF Type 0 stores all events in one track, Type 1 stores synchronized parts in multiple tracks, and Type 2 stores independent patterns. Type 0 and Type 1 are the formats most commonly supported by current software and hardware.

What the MIDI format is

In file-conversion software, “MIDI file” usually means a Standard MIDI File with a .mid or .midi extension. MIDI itself is a communications standard for musical control data; an SMF is the file format used to store that data for later playback.

A MIDI file contains instructions rather than sound. Playback uses the destination device’s synthesizer or virtual instrument, so the same file can sound different on different systems. Compared with audio, MIDI files are usually much smaller and let users edit notes, tempo, instruments, and controller data individually.

How to convert an SMF file

First check whether the .smf file is already a Standard MIDI File. Open it in a MIDI-capable application such as MuseScore, REAPER, Logic Pro, Cubase, Cakewalk, or another DAW or MIDI editor. If it opens and displays tracks or events, the file is usually already in SMF format.

For a direct header check on macOS or Linux, run:

xxd -l 4 composition.smf

The hexadecimal result 4d546864 represents the ASCII header MThd. An application that reports an unknown format, or a file without this header, should not be converted by simply changing its extension; it may use a proprietary format despite the .smf suffix.

If the file is valid SMF and only its extension prevents import, make a backup and rename a copy:

cp composition.smf composition.mid

On Windows, copy the file in File Explorer, enable View → Show → File name extensions if needed, and change composition.smf to composition.mid. Open the copy and verify that its tracks, tempo, time signature, and instruments are present.

For a validated re-save, import the file into a DAW, notation program, or MIDI editor, then choose File → Export or File → Save As and select Standard MIDI File or MIDI. Choose Type 0 when an older keyboard or sequencer requires one track, or Type 1 when separate tracks must be preserved. Save the result with a .mid extension.

The free converter on 101convert.com can perform the conversion without installing software: upload the SMF file, select MIDI as the output, run the conversion, and download the result.

Quality and compatibility limits

If both files are Standard MIDI Files, changing .smf to .mid changes only the filename extension and does not change musical data. Re-exporting through an application can change track grouping, event ordering, unsupported metadata, controller events, resolution, or the Type 0/Type 1 structure, so retain the original file.

MIDI conversion does not include the original instrument recordings or synthesizer sounds. Check that the destination preserves General MIDI program numbers, bank-select messages, tempo, time signature, sustain, modulation, pitch-bend, and other controller events. Older hardware may limit track count, timing resolution, filename length, or Type 1 support; Type 0 is generally the safer export choice for such devices.