Bulk AAC to M4B Converter Online — Free HD Quality
Drag and drop your multiple AAC files into this 100% free online AAC to M4B converter (.aac to .m4b), and click the Convert button to bulk convert them to M4B format in HD quality. Use the quality slider to fine-tune your M4B output, then download your converted files one by one or as a single ZIP — no signup and no downloads needed, and your original AAC files are removed from our servers right after. Also see:Bulk OPUS to WAV tool.
Drop your AAC files here to convert to M4B, or click to browse
Converts .aac to M4B (.m4b) in HD quality — bulk, free, no signup
Choose FilesAAC vs M4B — File Format Comparison
See how AAC and M4B compare across file extension, MIME type, compression, and feature support. Related:Free AAC to IPOD - no account needed.
| Feature | AAC | M4B |
|---|---|---|
| File Extension | .aac | .m4b |
| MIME Type | audio/aac | audio/mp4 |
| Compression Type | Lossy | Lossy |
| Metadata Support | Yes | Yes |
What Is AAC Format?
Advanced Audio Coding — the successor to MP3 adopted by Apple, YouTube, and mobile platforms; delivers better quality than MP3 at the same bitrate, especially below 128 kbps. See also:Bulk convert AAC to iPhone Audio.
- Compression: Lossy
- Tags & Metadata: Supported
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.
- Compression: Lossy
- Tags & Metadata: Supported