CastReader adds text-to-speech to UWorld. Click play on any question explanation — it reads aloud with paragraph highlighting and natural AI voices. Study while commuting, exercising, or cooking.
Built for exam prep — study smarter, not just harder
UWorld is the gold standard for USMLE, NCLEX, Bar, and other professional exam prep. Each question comes with detailed explanations — often 500+ words of critical reasoning. But there's no audio option. You're stuck reading on a screen, which limits when and how you can study.
CastReader extracts only the explanation text — paragraphs, headings, and bullet points. It skips navigation buttons, question numbers, answer choices UI, and other interface elements that don't belong in audio.
Each paragraph highlights as it's read aloud. Click any paragraph to jump there. The page auto-scrolls to follow along — perfect for visual reinforcement while listening.
Send audio to your phone via Telegram and listen to UWorld explanations during your commute, at the gym, or while doing chores. Turn dead time into study time.
Free to use, no signup. You're already paying for UWorld — CastReader adds audio at no extra cost. Upgrade to CastReader Pro for premium voices, more listening hours, and AI document analysis.
UWorld is the most trusted question bank for medical, nursing, legal, and financial exam prep. Whether you're studying for the USMLE Step 1, NCLEX-RN, Bar Exam, or CPA, UWorld's detailed explanations are what set it apart from competitors. Each question explanation breaks down the reasoning, covers related concepts, and includes educational tables — often running 500-1,000 words per question.
The challenge: UWorld has no built-in audio feature. Every minute of studying means sitting in front of a screen reading text. For students who spend 6-8 hours a day on exam prep, this creates eye strain, fatigue, and wasted commute time. Many students wish they could listen to explanations while walking, driving, or exercising.
CastReader solves this by adding intelligent text-to-speech directly to UWorld's web interface. Install the free Chrome extension, open any UWorld question, and click play. CastReader reads the explanation aloud with natural AI voices in 40+ languages, highlighting each paragraph as it goes. You can follow along visually or just listen.
The integration is smart about what it reads. UWorld pages contain navigation elements, answer choice buttons, performance metrics, and other UI that shouldn't be read aloud. CastReader's extraction engine identifies the explanation content and reads only the educational text — paragraphs, headings, lists, and key takeaways.
For maximum study efficiency, use CastReader's Send to Phone feature. Start reading an explanation on your computer, tap the phone icon, and continue listening on your phone via Telegram. This turns your commute, gym session, or household chores into productive study time — perfect for the months-long marathon of exam preparation.
Everything about UWorld text to speech
No, UWorld does not have a built-in text-to-speech feature. CastReader adds TTS to UWorld's web interface as a free Chrome extension. It reads question explanations aloud with natural AI voices and paragraph highlighting.
UWorld does not offer audio versions of its question explanations. CastReader fills this gap by converting any UWorld page into audio with intelligent content extraction that reads only the explanation text.
Yes. Install CastReader, open any UWorld USMLE question, and click play. CastReader reads the explanation aloud, skipping UI elements like answer buttons and navigation. Works with Step 1, Step 2 CK, and Step 3 content.
Yes. CastReader works with all UWorld question banks including NCLEX-RN, NCLEX-PN, USMLE, COMLEX, Bar Exam, CPA, CFA, and more. It reads any text content on the UWorld web platform.
CastReader works on desktop Chrome and Edge browsers. For mobile listening, use the Send to Phone feature — start reading on your computer and stream the audio to your phone via Telegram.
Yes — CastReader is free to use, no signup. You're already paying for your UWorld subscription, so CastReader adds audio at no extra cost. CastReader Pro (optional) adds premium ultra-realistic voices, more listening hours, voice cloning, and AI document analysis.
CastReader's smart extraction focuses on the explanation text — the detailed reasoning, educational content, and key takeaways. It skips answer choice buttons, navigation elements, and performance metrics.
CastReader supports 40+ languages with natural AI voices. While UWorld content is primarily in English, CastReader can read any language and automatically selects the appropriate voice.
Yes. CastReader lets you adjust the reading speed from 0.5x to 3x. Many students prefer 1.5x-2x speed for review sessions to cover more material in less time.
Yes. CastReader works on any UWorld page that contains text, including self-assessment exams, practice tests, and review modes. It reads the explanation content after you submit your answer.
With CastReader's Send to Phone feature, you can stream UWorld explanations to your phone and listen during your commute. Review the explanations for questions you've already answered — turning drive time into study time.
CastReader works with UWorld's web interface (accessed through Chrome or Edge browser), not the mobile app. For the best experience, use UWorld in your desktop browser with CastReader installed.
How TTS helps students study more effectively
Have a tough explanation broken down in your language
Why listening beats re-reading when focus drifts
Stream UWorld audio to your phone for mobile study
Turn technical books into audio on O'Reilly Learning
Turn study EPUBs into audio you can review on the go
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
Free to use. No signup. Turn every UWorld explanation into audio.
★★★★★ 4.7 · Free to start · No login · Optional Pro