Upload an EPUB, DOCX, or text file. Get a natural AI audiobook in seconds — free, no signup, no install.
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Supports PDF, EPUB, DOCX, TXT, MD, HTML
Other converters cap your usage or require paid plans. CastReader is free and unlimited.
Smart Parsing
CastReader understands EPUB structure — chapters, headings, paragraphs. It preserves reading order, skips formatting artifacts, and delivers clean audio chapter by chapter.
Every Format
Upload any ebook or document format. EPUBs from Project Gutenberg, Word documents from school, Markdown notes, plain text exports — they all work. We extract the text, clean it up, and convert it to natural speech.
Language Learning
Upload a document in French, Japanese, or Arabic. CastReader auto-detects the language and uses a native AI voice. Read along while listening — the best way to improve pronunciation and comprehension.
No Heavy Software
No installing Calibre, Adobe Reader, or desktop apps. Open this page, upload your file, listen. Works on Chromebooks, school laptops, borrowed computers — anywhere you have a browser.
EPUBs are the open standard for ebooks — structured HTML under the hood, with chapters, metadata, and styling baked in. Converting an EPUB to audio should be simple, and with CastReader it is. Upload your file, pick a voice, listen. No signup, no character limit, no subscription. The audio is generated using Kokoro, an open-source neural TTS model that sounds natural enough for hour-long listening sessions.
The catch is DRM. EPUBs purchased from Kindle, Kobo, or Apple Books are DRM-protected and won't work with any upload tool — the encryption prevents text extraction. If you bought an EPUB from a DRM-free source like Project Gutenberg, Humble Bundle, Smashwords, or a direct author sale, upload works perfectly. For DRM-locked ebooks, use the CastReader Chrome extension instead — it reads the text directly from the browser screen, bypassing DRM entirely.
DOCX and TXT files are even simpler — clean text in, clean audio out. Word documents from school, Markdown notes, plain text exports from note-taking apps. CastReader preserves paragraph structure and skips formatting artifacts. Upload a .docx term paper and get a listenable audio version in seconds.
The practical use cases go beyond 'listening to books.' Students convert lecture notes to audio for review. Language learners upload foreign-language novels and listen along while reading. Parents convert children's storybooks into bedtime audio. Teachers create audio versions of worksheets for students with reading difficulties. Writers listen to their own manuscripts to catch awkward phrasing.
For PDFs specifically — academic papers, textbooks, scanned documents — use our dedicated <a href='/pdf-to-audiobook'>PDF to Audiobook converter</a>, which handles multi-column layouts and OCR. For live webpages, Kindle books, or Google Docs, install the free CastReader Chrome extension.
Other tools that convert ebooks to audio — NaturalReader ($60/yr), Speechify ($139/yr), Voice Dream Reader ($5.99) — all charge money. CastReader is free. Voice quality is comparable. The difference is price: zero dollars, forever.
Common questions about converting ebooks and documents to audio
CastReader supports EPUB, DOCX, TXT, MD (Markdown), HTML, and PDF files. Upload any of these formats and get natural AI audio. For PDFs with complex layouts (academic papers, multi-column), we recommend the dedicated PDF to Audiobook converter.
Yes, 100% free. No signup, no credit card, no daily limits, no character caps. Upload as many ebooks as you want. Other tools like NaturalReader ($60/yr) and Speechify ($139/yr) charge for this feature — CastReader offers it for free.
No. DRM-protected files cannot be uploaded and converted. For Kindle books, use the free CastReader Chrome extension — it reads Kindle Cloud Reader directly using OCR, bypassing the text encryption. For DRM-free EPUBs (from Project Gutenberg, Humble Bundle, etc.), upload works perfectly.
Project Gutenberg (70,000+ free public domain books), Standard Ebooks (beautifully formatted classics), Humble Bundle (periodic ebook bundles), Smashwords, and direct author sales. Many indie authors sell DRM-free EPUBs on their websites. Our free audiobooks library also has thousands of public domain titles.
NaturalReader charges $60/year for document upload. Speechify charges $139/year. CastReader is free. Voice quality is comparable — all three use neural AI voices. CastReader's unique advantage: the free Chrome extension also reads live webpages, Kindle books, and Google Docs directly in your browser.
Yes. After your ebook is processed, you can play it in the browser and download individual chapters as MP3 files. Use them offline, on your phone, or in any audio player.
Yes. Upload any .docx file — term papers, lecture notes, reports — and CastReader converts it to natural AI audio. It preserves paragraph structure and skips formatting artifacts. Works with .txt and .md (Markdown) files too.
Absolutely. Upload an ebook in your target language — French, Japanese, Spanish, Arabic, or any of 40+ supported languages. CastReader auto-detects the language and uses a native AI voice. Read along while listening for maximum comprehension and pronunciation practice.
Yes. Your document is processed on our servers for text extraction and TTS generation, then the audio is available only to you. We don't share, sell, or use your documents for training. No account means no tracking — we don't even know who you are.
We support files up to 100MB. For long ebooks, the system processes them chapter by chapter. Each chapter becomes a separate audio track you can play or download independently. A 500-page novel typically takes about a minute to process.
File not opening correctly? Send it to our debug team
The only TTS that works on Kindle Cloud Reader — OCR bypasses encrypted fonts
70,000+ public domain books you can listen to for free
Convert any text to natural AI speech online — no signup, no limits
Side-by-side test of every free text-to-speech tool in 2026
How dual-channel reading helps — tools and techniques
How to read and listen to books online for free in 2026
Convert any PDF to a natural AI audiobook — handles academic papers & textbooks
Download the CastReader app to listen to your uploaded documents anywhere.
Hard numbers — not vibes — from authoritative sources
$2.22 billion
US audiobook sales in 2024, up 13% year-over-year (Publishers Weekly / Audio Publishers Association)
Source →51%
of US adults have listened to an audiobook in 2025 — roughly 134 million people (APA Consumer Survey 2025)
Source →2.2 billion
people globally with near- or far-vision impairment (WHO Fact Sheet, 2024). TTS is the primary access path for digital reading content.
Source →78%
of audiobook listeners multitask while listening — commute, chores, exercise (Audiolibrix Great Audiobook Survey, 2024)
Source →27.2 minutes
average single-trip US commute in 2024, up from 26.8 (US Census ACS via Statista). That's nearly an hour each day of audio-only time.
Source →effect size 0.35
measured comprehension lift from TTS for reading-disabled students across 22 studies (Wood, Moxley, Tighe & Wagner, Journal of Learning Disabilities, 2018)
Source →15.5 million
US adults with ADHD per CDC 2024 — about half diagnosed in adulthood (CDC MMWR, October 2024)
Source →Every Chrome Web Store review below is verifiable at the link in each card. We don't hide negative feedback — we answer it within 24 hours.
“This is 1 of the best TTS and its smooth. If this is truly free i'll keep this 100%. Every other TTS says its free but has a secret. They interrupt or they just say better ai voices pay. But i like this voice. I've tried loads and this is 1 of the best ones that actually says free.”
“Works perfectly on vivaldi. One suggestion though. I wish it had a play button appear next to a paragraph when we hover over it. Just like in the case of speechify.”
“Extremely user friendly short keys. Placed forward backward and speed up down as Natural as it could be. Voices are great and smooth. I would recommend it over many hyped products.”
“At the very least it's better than many paid TTS models. Still not as good as ElevenReader or LAP, but maybe the best free model for TTS.”
“So glad I can finally switch voices! The default was fine but I found one I actually enjoy listening to for hours. Small thing, huge difference.”
“Best one i found, user friendly, and great voice over.”
“ChatGPT's long answers are finally listenable. Let it generate while I listen — doubles my productivity. Love the inline button next to each response.”
“I tried using this add-on to listen to an ebook on the O'Reilly learning platform, and it works smoothly. However, it always restarts from the first paragraph whenever I scroll or select a different paragraph. Please consider adding a bookmark or checkpoint feature so users can mark where the reading should begin.”
↪ Founder reply
Replied by CastReader founder Yan Xu within 48 hours: acknowledged the issue, shipped a bookmark feature in the following release. Reviewer's verbatim feedback drove the v1.2 roadmap.
“Need to highlight text and select it.”
“Hard to select text.”
↪ Founder reply
Replied by CastReader founder Yan Xu within 24 hours: apologized, asked which site/browser the issue occurred on, provided a workaround using the keyboard shortcut, and offered direct support at support@castreader.ai.
We re-test, re-write, and ship continuously. Every entry has a real date.
Rewrote landing pages with verbatim Chrome Web Store testimonials, real audiobook market data, and tested-12-extensions methodology. Every claim now has a sourceable link.
Telegram audio streaming now auto-turns pages reliably across Kindle Cloud Reader and Apple Books. Reduces session interruptions by ~70% in internal testing.
Wrote up the OCR pipeline: how CastReader handles Amazon's 184 random font alphabets and 361 unique glyphs per Kindle book. Shared in dev.to.
Native macOS app reads Kindle for Mac with word-level highlighting. Floating player + system-wide hotkeys. No browser needed.
Ranked #10 in Daily, 99 upvotes, 4 community comments shaped the v1.2 roadmap.
Switched from older TTS engines to Kokoro neural voices. User reviews shifted from 'usable but robotic' to 'enjoy listening for hours' (verbatim from review by patrick chiang).
OCR success rate improved from 78% to 89% on English-language Kindle books. Multi-column page detection added for academic PDFs.
I built CastReader because I owned hundreds of Kindle books and couldn't listen to them on my morning runs without buying separate Audible copies. The technical problem — Amazon's Cloud Reader font encryption — turned out to be solvable with OCR. The product problem — making it actually pleasant across phones, desktops, and 40+ languages — took two years of iteration. We're a small team. I answer every Chrome Web Store review personally (see testimonials above — including the 3-star and 1-star ones). If something's broken or missing, email support@castreader.ai.
— Yan Xu, founder
Last reviewed: · CastReader Team — reviewed against 2025 testing data
Open EPUB / DOCX / TXT on any device. Free CastReader runs on Chrome / Edge / iOS / Android / Mac.
★★★★★ 4.7 · Free · No login · No limits