Free Resource
The Audiobook Submission Checklist
Master to this spec. Pass everywhere.
A one-page reference for self-narrating authors. Hit these specs and your files pass ACX, Voices by INaudio (formerly Findaway), Spotify for Authors, Google Play Books, Kobo Writing Life, and Apple Books — without separate masters per platform.
Audio quality specs
These are the numbers that get audiobooks rejected. Every chapter file must pass every spec.
RMS Loudness
The average loudness of the file across its full duration. Aim for -20 dBFS — the middle of the range. Files outside this window are rejected automatically.
True Peak
The loudest single moment in the file. Must use a true-peak-aware limiter, not just a sample-peak meter. Inter-sample peaks commonly cause rejections that look fine on a sample meter.
Noise Floor
The background sound level during silent passages. HVAC, computer fans, refrigerators, and untreated room acoustics are the usual culprits. Measured in the silent sections of your file, not the speech.
Sample Rate
The CD standard. Record at this rate from the start if your interface supports it — converting from 48 kHz introduces unnecessary processing.
Channel
Stereo files are rejected by ACX. Audiobooks are spoken word, not spatial audio. If you accidentally recorded in stereo, collapse to mono in your DAW before exporting.
Format
Not VBR. Not 128 kbps. Not 320 kbps. Specifically 192 kbps constant bit rate. ACX's automated check rejects variable bit rate files and anything below 192.
Head Silence
Brief silence at the start of each file before narration begins. Gives the listener a clear audio cue that content is starting.
Tail Silence
Brief silence at the end of each file after narration ends. Note: ACX measures RMS across the full file including silence padding, so generous tail silence will pull your measured loudness down slightly.
File structure (per chapter)
One file per chapter or section.
Each chapter, prologue, epilogue, opening credits, and closing credits gets its own MP3 file. Rights holders upload these individually.
File naming.
Use clear, sequential naming: 01_Opening_Credits.mp3, 02_Chapter_1.mp3, 03_Chapter_2.mp3, etc. Most platforms accept any clear naming convention; consistency matters more than format.
Section header at the start of each file.
"Chapter 1" spoken at the beginning of Chapter 1's file. "Prologue" spoken at the start of the prologue file. Consistent across the whole book.
Required separate files
Opening Credits file
Contains: book title, subtitle, author name, narrator name ("Read by [name]"). Usually 30–60 seconds.
Closing Credits file
Contains, at minimum: "The End." Often expanded to include copyright statement, narrator credit, production credits. Usually 30–60 seconds.
Retail Audio Sample
Between 1 and 5 minutes. Pulled from the first chapter or any representative section. Must start with narration — not opening credits, not music. Cannot contain explicit content even if the audiobook does.
Consistency rules
These are the rules that get audiobooks rejected after the automated check passes — when human QA reviewers spot inconsistencies.
Chapter-to-chapter loudness consistency.
Even if every chapter individually passes -23 to -18 dBFS RMS, if Chapter 3 is noticeably louder than Chapter 7, your audiobook can still be rejected for inconsistency. Master all chapters together, not separately.
Tonal consistency.
EQ, microphone, recording space, and time of day should be consistent across the whole audiobook. Recording Chapter 1 in your treated closet and Chapter 12 in your unfurnished kitchen will show up audibly even if specs pass.
Performance consistency.
Reading energy, pacing, and emotional register should match across sessions. Listeners notice abrupt shifts.
Pronunciation consistency.
Character names, place names, and unusual words must be pronounced the same way every time across the entire book. Keep a pronunciation guide as you record.
Common rejection reasons
- 1.RMS outside the -23 to -18 dBFS range — by far the most common issue
- 2.Noise floor above -60 dBFS — usually from untreated rooms or noisy equipment
- 3.True peaks above -3 dBFS — often from plosives (p/b sounds) or mouth clicks
- 4.Inconsistent loudness across chapters
- 5.Wrong format — WAV uploaded instead of MP3, VBR instead of CBR, stereo instead of mono, wrong sample rate
- 6.Missing head or tail silence — files starting or ending abruptly
- 7.Missing or inconsistent section headers
- 8.Sample contains explicit content or opening credits
Pre-submission verification
Before you upload to any platform, run this final check on every file:
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Platform notes
ACX (Audible, Amazon, Apple Books via ACX)
Strictest specs and the only fully automated check. Files passing here pass everywhere else.
Voices by INaudio (formerly Findaway)
Accepts FLAC alongside MP3, accepts stereo files, enforces a maximum chapter length. Master to ACX spec and you're safe.
Spotify for Authors
Accepts standard audiobook submissions. Less strict than ACX on automated checks. Has a separate AI-narration program for authors using generated voices — that's a different submission path.
Google Play Books
Accepts the same MP3 specs as ACX with broader format flexibility. ACX-spec files pass automatically.
Kobo Writing Life
Accepts ACX-spec files. Submission is generally less automated.
Apple Books (direct, not via ACX)
Has a separate Digital Narration program for AI-generated audio; standard human-narrated audiobooks typically go through ACX or aggregators.
A note from JM
This checklist is what 25 years of audio production has taught me matters when you submit an audiobook. The technical specs are non-negotiable — every platform measures them, and your file either passes or doesn't.
What matters more, and what no automated check catches, is whether you sound like you across the whole book. Production consistency is what separates an audiobook that gets finished by listeners from one that gets abandoned.
If you're producing your own audiobook and want the technical specs handled automatically while you focus on your performance, that's what TalkEditPro exists to do. Every file we export passes this checklist. Founders pricing is live.