M4B to WMA Converter
Convert M4B to WMA online for free. Fast, secure, and high-quality conversion with no sign-up or software required.
Maximum file size is 1GB
How it works
Three steps to your converted file
Everything happens in your browser tab - upload, pick a format, download. The heavy lifting runs on our servers.
Upload your file
Drag and drop, click to browse, or paste a URL. Batches take up to 20 files at once - 230+ input formats across video, audio, image, document, and archive types.
Choose an output format
Pick from over a hundred output formats. Filter by category or search by name - every option is open to everyone, no account needed.
Convert & download
Hit Convert and grab your download link moments later. Originals are erased when the job completes; results are cleared within about an hour.
What is an M4B file?
M4B is an MPEG-4 audio container file specifically structured for audiobooks and podcasts, functionally identical to M4A but supporting digital rights management (DRM) via Apple's FairPlay protection. Its distinguishing feature is the support for bookmarking metadata, allowing players to resume playback from the last stopping point, and chapter markers for navigation. The format typically utilizes AAC encoding within the ISO/IEC 14496-12 base media file format.
How to open an M4B file
Apple Books (formerly iTunes) is the primary software for opening DRM-protected M4B files on macOS and iOS. Unprotected M4B files can be played on VLC Media Player, Windows Media Player, and specialized audiobook readers like Smart Audiobook Player for Android. Attempting to play DRM-encrypted files on unauthorized non-Apple software will result in decryption errors.
M4B Technical Info
- Full Name
- MPEG-4 Audiobook
- Developed By
- Apple Inc.
- Initial Release
- 2003
- MIME Type
- audio/m4b
What is a WMA file?
Windows Media Audio (WMA) refers to a series of audio codecs and their corresponding Microsoft container format, designed as a competitor to MP3 and RealAudio. The standard WMA codec is lossy, but the format family includes WMA Lossless, WMA Pro (multichannel), and WMA Voice. It utilizes the Advanced Systems Format (ASF) container structure and supports digital rights management (DRM), which historically restricted playback to authorized Windows devices.
How to open a WMA file
WMA files are native to the Windows ecosystem and open by default in Windows Media Player and Movies & TV. macOS users require third-party components like Flip4Mac (legacy) or universal players such as VLC Media Player and Elmedia Player to decode the stream. Android and Linux support is generally provided via VLC or by installing ffmpeg-based media libraries.
WMA Technical Info
- Full Name
- Windows Media Audio
- Developed By
- Microsoft
- Initial Release
- 1999
- MIME Type
- audio/x-ms-wma
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The fastest way to convert any file
Purpose-built for speed, privacy, and breadth of format support.
Convert M4B to WMA in seconds
Every M4B to WMA conversion runs on our servers, so your device stays fast and the output quality stays intact.
Fast, cloud-powered
No queue, no waiting. Files are processed on high-performance servers and returned in seconds, even for large files.
Secure & private
Encrypted in transit and never shared with anyone. Uploads are erased the moment your job completes, and results shortly after.
Free - no account needed
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Developer API
Convert M4B to WMA via API
Automate M4B to WMA conversions in three steps: create a job, upload your file, then poll for the result.
# 1. Create job
curl -X POST https://api.runconvert.com/v3/jobs \
-H "Authorization: Bearer YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"tag": "m4b-to-wma",
"tasks": {
"upload-file": {
"operation": "import/upload"
},
"convert": {
"operation": "convert",
"input": "upload-file",
"output_format": "wma"
},
"export-result": {
"operation": "export/url",
"input": "convert"
}
}
}'
# 2. Upload your file (use upload_url from the response)
curl -X PUT "$UPLOAD_URL" --upload-file input.m4b
# 3. Poll for result
curl https://api.runconvert.com/v3/jobs/$JOB_ID?include=tasks \
-H "Authorization: Bearer YOUR_API_KEY"Replace YOUR_API_KEY with your RunConvert API key. Get your free API key at runconvert.com/api.