MP3 → M4B
Convert MP3 audio to M4B entirely in your browser — no upload, no watermark, no sign-up.
Drop files here
or browse from your device
images · audio · video · documents · archives · up to ~500MB
100% Private
Runs in your browser. No upload.
Instant
No queue, no server roundtrip.
Offline-ready
Works after first load.
MP3 is lossy and already stripped of detail, which limits what further editing can recover. M4B is the audiobook format Apple Books and podcast apps bookmark, resume and chapter properly, so converting turns a file you are stuck with into one you can actually use. Morphix runs the whole MP3 → M4B conversion locally with WebAssembly, so even confidential material never leaves your device.
Drop your MP3 file above and Morphix decodes it locally, then re-encodes it as M4B using WebAssembly + the browser's native codecs. Nothing is ever uploaded — your files stay on your device. Batch as many files as your machine can handle.
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