Bulk M4B to FLAC Converter Online — Free HD Quality
Drag and drop your multiple M4B files into this 100% free online M4B to FLAC converter (.m4b to .flac), and click the Convert button to bulk convert them to FLAC format in HD quality. Use the quality slider to fine-tune your FLAC output, then download your converted files one by one or as a single ZIP — no signup and no downloads needed, and your original M4B files are removed from our servers right after. Also see:Convert OGA files to WAV in queue.
Drop your M4B files here to convert to FLAC, or click to browse
Converts .m4b to FLAC (.flac) in HD quality — bulk, free, no signup
Choose FilesM4B vs FLAC — File Format Comparison
See how M4B and FLAC compare across file extension, MIME type, compression, and feature support. Related:Mass M4B to OPUS conversion.
| Feature | M4B | FLAC |
|---|---|---|
| File Extension | .m4b | .flac |
| MIME Type | audio/mp4 | audio/flac |
| Compression Type | Lossy | Lossless |
| Metadata Support | Yes | Yes |
What Is M4B Format?
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. See also:Convert M4B files to OGG in queue.
- Compression: Lossy
- Tags & Metadata: Supported
What Is FLAC Format?
Free Lossless Audio Codec — open-source lossless compression that reduces file size by 40–60% versus WAV with zero quality loss, perfect for audiophile archiving.
- Compression: Lossless
- Tags & Metadata: Supported