Your MP3s, one audiobook, with chapters

Drop a folder of MP3s, get a single M4B with chapter markers, cover art, and metadata for Apple Books, Audiobookshelf, and every audiobook player. Free, no upload, no sign-up.

Drop your MP3s here — the whole book at once

or click to choose · MP3, M4A, WAV, FLAC, OGG · built in your browser, never uploaded

Never uploaded

FFmpeg runs inside your browser as WebAssembly. A 10-hour book never leaves your disk — no account, no queue, no size cap.

Real chapters

One chapter per file, ordered by track number or natural filename order, titled from the tags. Edit any title before you build.

Cover and metadata from the tags

Title, author, narrator, year, and the embedded cover are read from your MP3s and written into the M4B — Apple Books and Audiobookshelf pick them up as-is.