Upload a .mid. Get the Game Boy version. Save as WAV or MIDI.
Wario Synth is a free online MIDI to 8-bit converter. Drop in a .mid or .midi file and the engine re-plays it through a synthesised Game Boy sound chip: two pulse channels, one wavetable channel, one noise channel. Nothing is uploaded — the conversion runs entirely in your browser with Web Audio.
You get an authentic 8-bit sound, not a bit-crushed MP3. Melody, bass, chords and drums are detected in the MIDI and mapped to the channels the real hardware had.
Dense files with many tracks work — the engine keeps the lead line and thins the rest to fit four voices. If a result sounds off, try another MIDI source: some are transcribed better than others.
v1 is the default: clean, punchy, forgiving of messy MIDI. v2 beta targets the real DMG chip more strictly — 15-bit LFSR noise, duty-cycle pulses, 4-bit wavetables. Switch tabs at the top of the app to compare.
Is it really free?
Yes. No account, no upload limit, no watermark. It's a hobby project.
Does my MIDI get uploaded?
No. The file is read in your browser and never leaves it. Only the shareable song search uses the network.
What formats come out?
WAV audio and a re-arranged .mid file mapped to the four Game Boy channels.
Can I convert MP3 to 8-bit?
Not directly. It needs note data, so start from a MIDI. Search the song name and Wario Synth finds a MIDI for you.