To convert M4B to AAC, select or drop your .m4b file above, check that AAC is chosen as the output, and click Convert. This conversion runs on our server, and your files are deleted 72 hours later.
What is a M4B file?
M4B – MPEG-4 audiobook (M4B). M4B is the same as M4A with a different name: audiobooks and podcasts use it so players remember where you stopped and can jump between chapters. Converting makes a new file: the sound is decoded and written again, so converting from a lossy format never brings back what was lost.
M4B Converter →What is an AAC file?
AAC – AAC audio. AAC is the successor of MP3: it sounds better at the same size. A bare .aac file is a stream of AAC frames; the usual home of AAC is the M4A file. Converting makes a new file: the sound is decoded and written again, so converting from a lossy format never brings back what was lost.
AAC Converter →How to convert M4B to AAC
- Click Select File, or drop your .m4b files anywhere on this page. You can add several at once.
- Check that AAC is chosen as the output format. On this page it is picked for you.
- Click Convert. When a file has to go to our server, the button says Upload and convert instead.
- Click Download next to each file when it's done.
M4B vs AAC: how they compare
| M4B | AAC | |
|---|---|---|
| Layout | A stream of sound | A stream of sound |
| Editable | In audio editors | In audio editors |
| Created by | Apple, 2005 | MPEG, 1997 |
| Best for | Audiobooks | Music on phones and streaming |
Good to know
- The sound is decoded and written as an AAC file at a fixed quality (192 kbit/s).
- Both are lossy, so converting costs a little quality each time: keep the original and convert from it when you can.
- Tags such as title and artist are kept where the new format has room for them. Only the first audio track is converted; pictures and video are left out.
Frequently asked questions
Is converting M4B to AAC free?
Yes. Everyone gets 25 free credits a day, with no account needed. Conversions on our server use one credit per started minute of work, so most cost a single credit. Credits reset at midnight UTC.
Are my M4B files uploaded anywhere?
This conversion runs on our server, because converting audio needs ffmpeg, which does not run in a browser. Your file is sent over an encrypted connection, and both it and the result are deleted 72 hours after the conversion. The server has no internet access while it works on your file.
How large can the M4B file be?
Up to 1 GB per file. This conversion runs on our server, which accepts files up to that size.
Will the AAC look the same as the M4B?
It sounds very close: the sound is encoded again as AAC at a fixed quality, so a little detail is lost, and tags such as title and artist are kept where AAC has room for them.
Can I convert several M4B files at once?
Yes. Add as many files as you like; they are converted one after another, and each one gets its own Download button.
How long does converting M4B to AAC take?
In our tests a one-hour WAV recording became an M4A file in about 46 seconds. A song of a few minutes takes a few seconds, and most conversions cost a single credit.
Convert M4B to other formats
- M4B Converter
- M4B to AIFF Converter
- M4B to FLAC Converter
- M4B to M4A Converter
- M4B to MP3 Converter
- M4B to WAV Converter
- M4B to WMA Converter
Convert other files to AAC
- Convert to AAC
- MP4 to AAC Converter
- MOV to AAC Converter
- MKV to AAC Converter
- AVI to AAC Converter
- WEBM to AAC Converter
- WMV to AAC Converter
- FLV to AAC Converter
- MP3 to AAC Converter
- WAV to AAC Converter
- M4A to AAC Converter
All audio formats
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