Convert M4B to M4A Online — Strip Chapter Markers
Convert M4B audiobook files to standard M4A format. Strips chapter metadata and bookmarks.
Drop up to 50 files at once — no install, no sign-up required.
Drop M4B Files Here
Encrypted EU Servers Auto-delete 1h
How it works
- 1 · Drop your files
Drag & drop or choose M4B files. No account required—paid plans unlock bigger batches, higher limits, and priority queues.
- 2 · We convert securely
Processed on our dedicated servers. Encrypted in transit & at rest. We never store filenames—only file types & sizes for accounting.
- 3 · Download & auto-delete
Grab your M4A files in seconds. Files delete automatically after 1 hour. Delete anytime after downloading with one click.
M4B is Apple's audiobook format, essentially an M4A file with chapter markers and bookmark support. Introduced with iTunes in 2003, M4B uses AAC audio encoding in an MPEG-4 container—the same codec as M4A—but with additional metadata for chapter navigation and resume-position bookmarks. This makes M4B ideal for long-form audio content like audiobooks and podcasts. Files from Audible (after DRM removal), iTunes Store, and Librivox commonly use M4B format.
Learn more: M4B on Wikipedia
M4B supports sample rates up to 96 kHz and multi-channel audio, though most audiobooks use mono or stereo at 44.1 kHz for efficiency. The chapter markers embedded in M4B files enable navigation to specific sections—a feature lost when converting to formats like MP3 or WAV. For maximum compatibility with car stereos, older MP3 players, and non-Apple devices, converting M4B to MP3 is often necessary. For archival or editing, WAV extraction provides lossless quality.
M4A (MPEG-4 Audio) is Apple's container format for AAC-encoded audio, introduced with iTunes in 2001. AAC itself was standardized by MPEG in 1997 (MPEG-2) and enhanced in 1999 (MPEG-4), achieving compression ratios of 8:1 to 12:1. M4A has become synonymous with Apple's ecosystem—it's the default for iTunes purchases, Apple Music downloads, and iPhone voice memos. At equivalent bitrates, AAC delivers better quality than MP3, with 256 kbps M4A typically matching 320 kbps MP3.
Learn more: M4A on Wikipedia
M4A supports sample rates up to 96 kHz and up to 48 audio channels, including surround sound configurations. The main limitation is compatibility—while modern devices handle M4A well, older hardware and some software (particularly on Windows and Linux) may not support it natively. For universal playback, MP3 remains the safer choice. M4A excels for Apple-centric workflows: syncing to iPhone, organizing in iTunes/Music app, or archiving Apple Music downloads.
Frequently Asked Questions
What is the difference between M4B and M4A?
Will converting M4B to M4A reduce audio quality?
Why would I convert M4B to M4A?
What happens to chapter markers and bookmarks?
How do file sizes compare between M4B and M4A?
What happens to iTunes metadata and album art?
How long can my audio files be?
What are the limits for this converter?
| Tier | Max File Size | Max Files/Batch | Parallel Processing |
|---|---|---|---|
| Free | 50 MB | 50 files | 3 at once |
| Pro | 500 MB | 200 files | 6 at once |
| Business | 2048 MB | 1000 files | 10 at once |
Note: File size limits are specific to this converter. Batch and parallel processing limits apply to all images converters site-wide. See all converter limits →
How are credits calculated for this conversion?
Cost: 1 credit per 5 minutes
How it works:
- Files up to 5 minutes: 1 credit (minimum)
- 6-10 minutes: 2 credits
- 11-15 minutes: 3 credits
- 16-20 minutes: 4 credits
Example: A 10-minute file = 1 credit. A 180-minute (3h) audiobook = 36 credits.
Why per-minute? Audio conversion time scales with content duration, not file size. Longer audio requires proportionally more processing.
What are my daily and monthly credit limits?
Credit allocations vary by account tier:
| Tier | Daily Limit | Monthly Limit |
|---|---|---|
| Free | 50 credits/day | — |
| Pro | — | 10,000 credits/month |
| Business | — | 30,000 credits/month |
Daily credits (Free tier, including guests) reset every day at midnight UTC. Monthly credits (Pro & Business) reset on your billing cycle date.
Note: With 1 credit per 5 minutes, audio files under 5 MB cost 1 credit each. Pro users can convert 10,000 audio files per month.
Answers at a Glance
Quick answers to common questions.
- Are my files secure?
- How long do you keep my files?
- What metadata do you keep?
- What happens after I drop a file?
- Why are conversions so fast?
- How do you measure performance?
- What are the exact limits for each plan?
- Can I process files in bulk?
- Why did my file fail to convert?
- Do you use my files to train AI?
Choose Your Plan
Limits shown for M4B to M4A conversion. One subscription unlocks the entire Tools.FAST Network. Plans cover Convert.FAST, Compress.FAST, PDF.FAST (soon), and all future tools.
Free
For occasional personal use
- 50 MB per file
- 50 files per batch
- 3 parallel conversions
- 50 credits/day
- Standard priority
- Email support
No sign-up required. Create an account for your own credit pool.
Pro
For independent work
- 500 MB per file
- 200 files per batch
- 6 parallel conversions
- 10,000 credits/month across Tools.FAST
- High priority
- Email & chat support
- One subscription for the entire Tools.FAST network
Business
For production scale
- 2 GB per file
- 1000 files per batch
- 10 parallel conversions
- 30,000 credits/month across Tools.FAST
- Add seats to invite team members
- Highest priority
- Priority email & chat support
- One subscription for the entire Tools.FAST network
How Credits Work
- Usually 1 credit per conversion. Exact cost shown before you start.
- Credits refresh monthly on your billing cycle.
- Unused credits roll over, capped at your plan's monthly amount.
- One subscription, all sites. Works across Convert.FAST, Compress.FAST, and future tools.
What's New in M4B to M4A
Latest improvements to this converter
Initial release of M4B to M4A converter for stripping audiobook chapter metadata.