Bulk WMA to M4B Converter Online — Free HD Quality
Drag and drop your multiple WMA files into this 100% free online WMA to M4B converter (.wma 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 WMA files are removed from our servers right after. Also see:Turn WAV into M4A.
Drop your WMA files here to convert to M4B, or click to browse
Converts .wma to M4B (.m4b) in HD quality — bulk, free, no signup
Choose FilesWMA vs M4B — File Format Comparison
See how WMA and M4B compare across file extension, MIME type, compression, and feature support. Related:Free WMA to M4R - no account needed.
| Feature | WMA | M4B |
|---|---|---|
| File Extension | .wma | .m4b |
| MIME Type | audio/x-ms-wma | audio/mp4 |
| Compression Type | Lossy | Lossy |
| Metadata Support | Yes | Yes |
What Is WMA Format?
Windows Media Audio — Microsoft's proprietary lossy audio codec bundled with Windows Media Player, commonly found in legacy Windows media libraries and early-2000s digital music stores.
- 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