Free Bulk M4B Audio Converter Online — 49+ Formats
Drag and drop your files into this free online M4B converter (audio/mp4, .m4b, Lossy), pick a target format from 49+ options and click the Convert button to change formats in HD quality. Use the quality slider to control file size and detail, then download each result separately or grab the whole batch as a single ZIP — no signup, no watermark, your M4B files deleted from our servers right after.
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Max 100MB per file
Most Popular Free M4B Conversions
All M4B Conversion Formats With 49+ Output Options
webp png jpg gif avif jxl jp2 bmp ico cur tiff tga pcx wbmp dds sgi pbm pgm ppm pnm pam xbm xpm ras pdf mp3 wav flac ogg aac m4a aiff opus wma amr alac mp2 m4r aif aifc caf 3ga oga ape wave iphone ipad ipod android
49 free M4B conversion formats available with bulk and batch support
What Is M4B Format and Why Convert It Online?
MPEG-4 Audiobook — AAC audio in an MP4 container with bookmarking support, the standard format for audiobooks on Apple Books, Audible exports, and iPhone podcasts.
| Property | M4B Details |
|---|---|
| File Extension | .m4b |
| MIME Type | audio/mp4 |
| Compression Type | Lossy |
| Metadata Support | Yes |
| Available Output Formats | 49+ formats |
- Bulk and batch conversion that lets you upload and convert multiple M4B files at once to any of 49+ supported formats
- 100% free with no signup so you can start converting M4B files instantly without creating an account
- Private and secure because all uploaded files are auto-deleted from our servers immediately after conversion