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Convert M4B to WAV Online — Lossless Audio

Extract M4B audiobook audio to lossless WAV format for editing or archival.

Drop up to 50 files at once — no install, no sign-up required.

Drop M4B Files Here

50 MB or 2 hours per file Up to 50 files (2 GB limit) 3 parallel conversions 1 credit per 5 minutes

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Median M4B → WAV time (last 10k jobs): 77ms per minute

How it works

  1. 1 · Drop your files

    Drag & drop or choose M4B files. No account required—paid plans unlock bigger batches, higher limits, and priority queues.

  2. 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. 3 · Download & auto-delete

    Grab your WAV 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.

WAV (Waveform Audio File Format) is an uncompressed audio format developed by Microsoft and IBM in 1991. It stores raw PCM (Pulse Code Modulation) audio data, preserving every sample from the original recording without any quality loss. WAV supports 16/24/32-bit depth, sample rates from 8 kHz to 192 kHz (commonly 44.1/48 kHz), and up to 65,535 channels. It's the standard working format for audio professionals in recording studios, broadcast facilities, and sound design workflows worldwide.

Learn more: WAV on Wikipedia

The main tradeoff is file size: a 3-minute stereo track at CD quality (44.1kHz, 16-bit) is approximately 30 MB. While this makes WAV impractical for streaming or portable devices, it remains essential for editing, archiving, and any workflow where audio quality is paramount. Converting to MP3 reduces file size by 90% or more while maintaining perceptually transparent quality for most listeners.

Frequently Asked Questions

What is M4B and why convert to WAV?

M4B is Apple's audiobook format—essentially an M4A file with chapter markers and metadata. WAV is uncompressed PCM audio, the gold standard for lossless archival and professional editing. Converting M4B to WAV gives you bit-perfect audio with no quality loss, ideal for audio restoration, remixing, or archival purposes.

Will converting M4B to WAV improve audio quality?

No. WAV is lossless, but it cannot recover quality already lost in the M4B encoding process. M4B files use AAC compression, which is lossy. Converting to WAV simply stores the decoded audio without further compression—it preserves the existing quality but doesn't enhance it. If you need a smaller file for everyday listening, try our M4B to MP3 converter instead.

Why are WAV files so much larger than M4B?

WAV stores raw PCM audio data without compression. A typical M4B audiobook at 64 kbps AAC might be 50-100 MB, while the same content as WAV could be 500 MB - 1 GB or more. This 10-20x expansion is normal. WAV prioritizes quality and editability over file size.

What WAV settings do you use?

We output 16-bit PCM WAV, preserving the source sample rate and channel layout. This preserves the full fidelity of the M4B source. WAV uses standard PCM encoding with no compression, ensuring bit-perfect lossless output.

Do chapter markers transfer to WAV?

No. WAV is a simple audio container with no support for chapter markers or metadata. M4B chapter information is lost during conversion. If you need chapters, consider keeping the original M4B or converting to FLAC with cue sheets instead.

How long can my M4B audiobooks be?

Duration limits depend on your plan: Guest/Free: 120 minutes, Pro: 600 minutes (10 hours), Business: 3000 minutes (50 hours). This accommodates everything from short audiobooks to full 10+ hour epics.

When should I use WAV instead of keeping M4B?

Use WAV for audio editing or archival. If you plan to edit audio in a DAW (Audacity, Adobe Audition, Logic Pro), apply effects, or create lossless backups, WAV is ideal. For everyday listening on mobile devices or car stereos, consider our M4B to M4A converter—it keeps the same codec with smaller file sizes than WAV.

What are the limits for this converter?

TierMax File SizeMax Files/BatchParallel Processing
Free50 MB50 files3 at once
Pro500 MB200 files6 at once
Business2048 MB1000 files10 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:

TierDaily LimitMonthly Limit
Free50 credits/day
Pro10,000 credits/month
Business30,000 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.

Choose Your Plan

Limits shown for M4B to WAV conversion. One subscription unlocks the entire Tools.FAST Network. Plans cover Convert.FAST, Compress.FAST, PDF.FAST (soon), and all future tools.

Monthly Annual 4 Months Free

Free

$0

For occasional personal use

  • 50 MB per file
  • 50 files per batch
  • 3 parallel conversions
  • 50 credits/day
  • Standard priority
  • Email support
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No sign-up required. Create an account for your own credit pool.

Popular

Pro

$9 /month

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

$19 /month

1 seat

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 WAV

Latest improvements to this converter

Last updated December 16, 2025
Dec 16, 2025

Initial release of M4B to WAV converter with lossless PCM audio extraction.