Bulk M4B to AMR Converter Online — Free HD Quality
Drag and drop your multiple M4B files into this 100% free online M4B to AMR converter (.m4b to .amr), and click the Convert button to bulk convert them to AMR format in HD quality. Use the quality slider to fine-tune your AMR 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:Online OGA to WAV converter tool.
Drop your M4B files here to convert to AMR, or click to browse
Converts .m4b to AMR (.amr) in HD quality — bulk, free, no signup
Choose FilesM4B vs AMR — File Format Comparison
See how M4B and AMR compare across file extension, MIME type, compression, and feature support. Related:Bulk convert M4B to AIFF.
| Feature | M4B | AMR |
|---|---|---|
| File Extension | .m4b | .amr |
| MIME Type | audio/mp4 | audio/amr |
| Compression Type | Lossy | Lossy |
| Metadata Support | Yes | No |
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:Switch M4B to OPUS format.
- Compression: Lossy
- Tags & Metadata: Supported
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.
- Compression: Lossy
- Tags & Metadata: Not supported