RunConvert
Sign In

M4B to M4A Converter

Convert M4B to M4A online for free. Fast, secure, and high-quality conversion with no sign-up or software required.

Free to useNo file stored beyond 1 hourEncrypted over TLS 1.2/1.3No watermarks

Like RunConvert? Set us as a preferred source on Google.

Add to Preferred Sources

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.

01

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.

02

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.

03

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 an M4A file?

The M4A file extension denotes an audio-only MPEG-4 container, defined by ISO/IEC 14496-14 standards and typically encoded using Advanced Audio Coding (AAC) or Apple Lossless (ALAC). Originally popularized by Apple to differentiate audio content from standard .MP4 video files, the container utilizes an atom-based structure (e.g., ftyp, moov, mdat) to store audio streams and metadata. It serves as the successor to MP3, offering superior compression efficiency and fidelity at equivalent bitrates.

How to open an M4A file

M4A files are natively supported by the Apple ecosystem (iTunes, QuickTime, iOS Music) and Windows Media Player on modern Windows versions. Cross-platform compatibility is robust, with VLC Media Player, Audacity, and Winamp providing decoding capabilities. On Android devices, native players often handle M4A, though third-party apps like Poweramp ensure compatibility with ALAC-encoded variants.

M4A Technical Info

Full Name
MPEG-4 Audio
Developed By
Apple Inc. / MPEG
Initial Release
2001
MIME Type
audio/mp4

More tools

Related conversions

M4B to AAC

M4B to AIFF

M4B to FLAC

M4B to M4B

M4B to MP3

M4B to WAV

M4B to WMA

AAC to M4A

Why RunConvert

The fastest way to convert any file

Purpose-built for speed, privacy, and breadth of format support.

Convert M4B to M4A in seconds

Every M4B to M4A 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

Convert without creating an account - no credit card, no trial clock. Sign in only if you want history and higher daily limits.

Developer API

Convert M4B to M4A via API

Automate M4B to M4A 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-m4a",
    "tasks": {
      "upload-file": {
        "operation": "import/upload"
      },
      "convert": {
        "operation": "convert",
        "input": "upload-file",
        "output_format": "m4a"
      },
      "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.