Convert WMA to M4B

WMA to M4B converter that runs entirely in your browser. 100% free, no signup, no upload — your files never leave your device. One-click batch conversion.

Conversions

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All file types supported

About formats

WMA

WMA (Windows Media Audio) is an audio compression format developed by Microsoft as part of the Windows Media framework. WMA was designed to compete with MP3 and AAC and offers good quality at low bitrates, with support for DRM copy protection. WMA is supported by Windows Media Player and many portable media players.

Developer: Microsoft
Initial release: 1999
Compression: Lossy or lossless
Color depth: up to 24-bit
Transparency: No
Animation: No

Best for

Windows Media Player audio
Corporate audio distribution with DRM
Legacy Windows audio archives
Low-bitrate streaming audio
Windows-ecosystem music storage

Pros

+Good quality at low bitrates
+Supports DRM copy protection
+Native Windows Media Player support
+Offers a lossless variant (WMA Lossless)

Cons

−Proprietary Microsoft format
−Poor support on non-Windows platforms
−Less universal than MP3 or AAC
−DRM limits portability

M4B

M4B is an MPEG-4 audio container variant specifically designed for audiobooks. It is identical to M4A in structure but supports chapter markers and bookmarking so players can resume playback. M4B is commonly used by iTunes and Apple Books.

Developer: Apple
Initial release: 2003
Compression: Lossy or lossless
Color depth: up to 24-bit
Transparency: No
Animation: No

Best for

Distributing audiobooks with chapters
iTunes and Apple Books audio
Bookmarkable spoken-word content
Long-form audio with navigation
Resumable podcast delivery

Pros

+Supports chapter markers and bookmarking
+Resumes playback across devices
+Identical audio quality to M4A
+Recognized by iTunes and Apple Books

Cons

−May carry FairPlay DRM
−Less universal than plain MP3
−Primarily Apple-ecosystem format
−Some players ignore chapter markers

How to convert WMA to M4B

1
Select WMA files from your computer, Google Drive, Dropbox, a URL, or by dragging them onto the page.
2
Choose m4b — or any other format you need as a result (more than 200 formats supported).
3
Let the file convert, then download your m4b file right away.

WMA vs M4B

Property	WMA	M4B
Compression	Lossy or lossless	Lossy or lossless
Color depth	up to 24-bit	up to 24-bit
Multi-track	Yes	Yes
DRM support	Yes	Yes
Open format	No	No

When to use WMA vs M4B

WMA

Windows Media Player audio
Corporate audio distribution with DRM
Legacy Windows audio archives
Low-bitrate streaming audio
Windows-ecosystem music storage

M4B

Distributing audiobooks with chapters
iTunes and Apple Books audio
Bookmarkable spoken-word content
Long-form audio with navigation
Resumable podcast delivery

Use cases for WMA → M4B

Windows Media Player audio
Corporate audio distribution with DRM
Legacy Windows audio archives
Low-bitrate streaming audio
Windows-ecosystem music storage
Distributing audiobooks with chapters
iTunes and Apple Books audio
Bookmarkable spoken-word content
Long-form audio with navigation
Resumable podcast delivery

Frequently Asked Questions

Is converting WMA to M4B free?

Yes. This WMA → M4B converter runs entirely in your browser and is completely free — no account, no credits, no watermark.

Which devices and platforms can I use to convert WMA to M4B?

Any modern device with a current web browser: Windows, macOS, Linux, Android, iPhone and iPad. There is nothing to install — the conversion happens locally.

Are my WMA files uploaded to a server?

No. Files never leave your device. The entire WMA → M4B conversion runs locally in your browser, so your data stays private.

Can I convert multiple WMA files at once?

Yes — batch conversion is supported. Add as many WMA files as you like and convert them to M4B in one pass, then download the results together.

What is the maximum file size?

There is no fixed server-side limit because the conversion happens in your browser. Practical limits depend on the available memory and CPU of your device.

Will converting WMA to M4B reduce the quality?

Because both formats use lossy compression, the M4B output will not bring back any quality that has already been lost in your WMA file. Avoid repeated re-encoding to keep the best quality.

Does M4B support transparency?

No — M4B has no alpha channel. Transparent areas of your WMA file will be filled with a solid background colour in the converted file.

How will the file size change after converting WMA to M4B?

Both formats use comparable compression, so the M4B output will be similar in size to your WMA file — typically within 10–20% of each other.

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FREE

100% Free

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SIGNUP

No Signup Required

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PRIVACY

Private & Secure

Your files never leave your device. All processing is completed locally for maximum privacy.

BATCH

Batch Conversion

Convert multiple files simultaneously to save time. Fast and efficient multi-file queue.

LOCAL

Runs in Browser

Utilizes advanced client-side WebAssembly technology to process files directly inside your tab.

FORMATS

200+ Formats

Supports a wide variety of formats including images, documents, audio, video, and more.

USER REVIEWS

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