Bulk AMR to M4B Converter Online — Free HD Quality
Drag and drop your multiple AMR files into this 100% free online AMR to M4B converter (.amr 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 AMR files are removed from our servers right after. Also see:Bulk convert PCM to WAV.
Drop your AMR files here to convert to M4B, or click to browse
Converts .amr to M4B (.m4b) in HD quality — bulk, free, no signup
Choose FilesAMR vs M4B — File Format Comparison
See how AMR and M4B compare across file extension, MIME type, compression, and feature support. Related:Convert WMA files in bulk to WAVE.
| Feature | AMR | M4B |
|---|---|---|
| File Extension | .amr | .m4b |
| MIME Type | audio/amr | audio/mp4 |
| Compression Type | Lossy | Lossy |
| Metadata Support | No | Yes |
What Is AMR Format?
Adaptive Multi-Rate — the standard voice codec for GSM and UMTS mobile networks, used in phone call recordings and voice messages; delivers compact files optimised for speech at 8 kHz. See also:Convert AMR to FLAC free.
- Compression: Lossy
- Tags & Metadata: Not 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