Audio conversion
Convert MP3 to M4B
MP3 is a plain audio file. M4B is the audiobook format that remembers where you stopped, and can support chapter navigation when a file has chapter markers. To convert MP3 to M4B, open the file in a converter and export it in the M4B container. Doing this on your own computer means the recording never has to leave your machine.
All 2,748 conversions verified on macOS, Windows, and Linux against the shipping release, this one included. Every conversion runs entirely on your own computer.
- Extension
- .mp3
- Type
- Audio
- Typically
- The universal audio format
- Compression
- Lossy
- Extension
- .m4b
- Type
- Audio
- Typically
- Audiobooks, podcasts
- Compression
- Lossy
Convert MP3 to M4B on your own computer. Nothing uploads.
One-time purchase, no subscription. 14 days to change your mind.
How to convert MP3 to M4B
- Open Morphjet and drag in the MP3 file you want to convert. Add one file or a whole folder at once.
- Choose M4B as the output format.
- Convert. The M4B is written next to your original, and nothing leaves your machine.
MP3 vs M4B: what actually changes
| MP3 | M4B | |
|---|---|---|
| Remembers your place | No, most players restart from the beginning | Yes, audiobook apps bookmark where you stopped |
| Chapters | No chapter markers, just one track | Still one track; converting doesn't add chapters on its own |
| Opens everywhere | Yes, every device and app plays MP3 | Mainly audiobook and podcast apps |
| Quality | Already compressed | Compressed again on export, a small extra loss |
| File size | Compact | Similar, sometimes smaller for spoken word |
| Metadata | Title, artist, album tags | Author and book title fields, plus cover art |
When to convert, and when not to
Convert MP3 to M4B when you want a recording, podcast episode, or spoken-word file to behave like an audiobook, with resume playback in audiobook apps. Converting one MP3 gives you one M4B track, not a chaptered book; it won't split into chapters on its own.
Keep the MP3 if you just need a plain audio file that plays anywhere without needing a dedicated audiobook app.
Why not just use an online converter?
Audiobook and podcast files are often long personal recordings, sometimes hours of someone's own voice. An online converter means uploading that entire file to a stranger's server and waiting for it to come back. Converting on your own computer keeps the recording on your machine the whole time, and it works with your wifi off.
Questions
Does converting MP3 to M4B lose quality?
A little. MP3 is already compressed, and packaging it as M4B re-encodes the audio, which adds a small extra loss. For spoken word like audiobooks and podcasts, it's generally not noticeable.
Will the M4B remember where I stopped listening?
Yes, that's the main reason people convert. Audiobook apps treat M4B differently from a regular music file and bookmark your position automatically, which plain MP3 playback usually doesn't do.
Does converting a single MP3 add chapter markers automatically?
No. A single MP3 becomes a single M4B track with no chapters. Converting a whole folder of MP3s works the same way: each file becomes its own separate M4B track, they aren't merged into one chaptered audiobook. If you want chapters, you need markers added before or after conversion.
Does M4B keep the title and artist info from the MP3?
The basic tags carry over, though M4B is built around audiobook fields like author and book title rather than the artist and album fields MP3 uses, so you may want to double check them after converting.
Can I convert MP3 to M4B without uploading the file anywhere?
Yes. A desktop app like Morphjet converts the file on your own computer, so the audio never travels over the internet.
Morphjet runs this conversion and 2,747 others, all on your machine. Available now.
One-time purchase, no subscription. 14 days to change your mind.