Free Audio to MIDI Converter (No Upload)

Upload an MP3, WAV, OGG, FLAC, or M4A file and it transcribes to a downloadable .mid file entirely in your browser — nothing is sent to a server. The tool runs Spotify's open-source Basic Pitch model via TensorFlow.js, decoding your audio down to mono 22.05kHz before feeding it through the model frame by frame. Because everything happens on-device, there's no queue, no account, and no upload wait — a 3-minute song typically transcribes in under a minute, faster on a GPU-capable browser and slower (but still working) on CPU-only fallback.

Basic Pitch does polyphonic transcription, meaning it can detect multiple simultaneous notes — chords on a piano or guitar, not just a single melody line. Many simpler pitch-detection converters only track one note at a time and produce a broken, monophonic mess on anything but a solo voice or instrument. The output MIDI file includes pitch, timing, velocity (how hard each note was played, inferred from volume), and pitch bends where the model detects sliding pitch — useful for guitar bends or vocal slides. Every note lands on a single MIDI track, ready to drag into a DAW like Ableton, Logic, or FL Studio.

Accepted input formats are MP3, WAV, OGG, FLAC, and M4A, up to 100MB per file. There's also a 20-minute duration cap — the model processes roughly 1.6 seconds of audio per inference step, so a 20-minute file already means hundreds of sequential model calls, and going longer starts to strain what a browser tab can comfortably handle. If no clear pitched content is detected (pure noise, spoken word with no melody), the tool tells you rather than returning an empty or garbled file.

Source quality matters more than file format. A dry, clearly-recorded instrument or vocal track transcribes far more accurately than a dense studio mix with heavy reverb, distortion, or multiple competing instruments in the same frequency range — the model has to guess harder when notes overlap or blur together. If you're transcribing a full song, isolating the instrument you care about first (even a rough vocal/instrumental split) usually beats feeding in the whole mix. Solo piano, solo guitar, and single-vocal recordings are the most reliable inputs.

Producers sketching a chord progression from a voice memo, musicians transcribing a riff they can't read but can play, and anyone turning a hummed melody into sheet music or a DAW project all use audio-to-MIDI converters the same way: as a starting point, not a finished transcription. Expect to clean up a few notes by hand afterward, especially in busier passages — that's normal for any automatic transcription tool, not a sign something's broken. Because the whole process runs locally, it's also fine to use on a rough phone recording or an unreleased demo you'd rather not upload anywhere.