M4B Converter
Convert files to and from M4B online for free. Fast, secure, and high-quality file conversion with no sign-up or software required.
Maximum file size is 1GB
Like RunConvert? Set us as a preferred source on Google.
Add to Preferred SourcesHow it works
Three steps to your converted file
Everything happens in your browser tab - upload, pick a format, download. The heavy lifting runs on our servers.
Upload your file
Drag and drop, click to browse, or paste a URL. Batches take up to 20 files at once - 230+ input formats across video, audio, image, document, and archive types.
Choose an output format
Pick from over a hundred output formats. Filter by category or search by name - every option is open to everyone, no account needed.
Convert & download
Hit Convert and grab your download link moments later. Originals are erased when the job completes; results are cleared within about an hour.
What is an M4B file?
M4B is an MPEG-4 audio container file specifically structured for audiobooks and podcasts, functionally identical to M4A but supporting digital rights management (DRM) via Apple's FairPlay protection. Its distinguishing feature is the support for bookmarking metadata, allowing players to resume playback from the last stopping point, and chapter markers for navigation. The format typically utilizes AAC encoding within the ISO/IEC 14496-12 base media file format.
How to open an M4B file
Apple Books (formerly iTunes) is the primary software for opening DRM-protected M4B files on macOS and iOS. Unprotected M4B files can be played on VLC Media Player, Windows Media Player, and specialized audiobook readers like Smart Audiobook Player for Android. Attempting to play DRM-encrypted files on unauthorized non-Apple software will result in decryption errors.
M4B Technical Info
- Full Name
- MPEG-4 Audiobook
- Developed By
- Apple Inc.
- Initial Release
- 2003
- MIME Type
- audio/m4b
More tools
Related conversions
Why RunConvert
The fastest way to convert any file
Purpose-built for speed, privacy, and breadth of format support.
3,000+ conversions supported
Every popular and niche format covered - video, audio, image, document, archive and more. New formats added regularly.
Fast, cloud-powered
No queue, no waiting. Files are processed on high-performance servers and returned in seconds, even for large files.
Secure & private
Encrypted in transit and never shared with anyone. Uploads are erased the moment your job completes, and results shortly after.
Free - no account needed
Convert without creating an account - no credit card, no trial clock. Sign in only if you want history and higher daily limits.