Compare · NaturalReader
The on-device NaturalReader alternative for iPhone and iPad
People look for a NaturalReader alternative for two reasons: the good voices sit behind a subscription, and the documents you want read have to be sent to a server to be read. Sandbook answers both — a free iPhone and iPad app with a neural speech model inside it — while doing considerably less than NaturalReader in other respects.
iOS 18.2 or later · iPhone 12 or later & iPad · No account
In short
Is there a free NaturalReader alternative for iPhone that works offline?
Sandbook is free on iPhone and iPad with the speech model on the device, so nothing is metered — where NaturalReader's free plan allows 20,000 characters a day on Lite voices and 4,000 on the tiers above. NaturalReader wins on languages, formats and playback: 200+ voices in 90+ languages, Word import, and background playback. Sandbook has 41 voices in six languages, scans printed pages on the device, and needs iOS 18.2 on an iPhone 12 or later; its real-time reading pauses when the screen locks.
Last verified 28 September 2026
A NaturalReader alternative with a different shape
NaturalReader is a text-to-speech platform with a long history: a web app, a Chrome extension and mobile apps, with 200+ AI voices across 90+ languages, OCR camera scanning, and cloud file pickers for Google Drive, Dropbox and OneDrive. It is free to start, and the voices most people want are on the paid plans.
Sandbook is one iPhone and iPad app that bundles Kokoro-82M, an open-weights neural TTS model, and runs it on the device's own GPU. 41 voices in six languages, free, no account, no server doing the speaking. EPUB, PDF, TXT, RTF, Markdown and HTML, web pages, camera scans and pasted text.
Those are different products. Choosing between them is mostly a question of whether you need breadth or privacy.
The subscription question
NaturalReader's free tier is genuinely usable, and it is metered in characters rather than minutes: unlimited listening on the device's own system voices, then 20,000 characters a day on Lite voices and 4,000 shared characters a day on Plus and Cloned voices, with no MP3 export and no OCR. To read a whole book in the good voices you move onto a plan.
Which price you see depends on where you buy, and the difference is not small. On the vendor website the ladder reads Lite $13.90/month or $79/year, Plus $20.90/month or $119/year, Pro $25.90/month or $159/year. The US iOS App Store in-app-purchase list has been neither renamed nor repriced: it still sells the entry tier as "Premium Plan" at $9.99/month or $59.99/year — the same tier the website now calls Lite and prices at $13.90/month (vendor website). NaturalReader says as much itself, "Premium has been renamed to Lite", and notes that prices may vary by region when you subscribe through the App Store. Plus and Pro are identical at both counters. All of it was read on 14 September 2026.
Sandbook has no plans. There is one voice tier — every one of the 41 voices runs the same 82-million-parameter model at 24 kHz — and no in-app purchase to reach it. There is no character allowance either, because nothing is being metered on a server.
That is only an advantage if six voice languages are enough for you: US and UK English (28 voices), Spanish, French, Italian, Brazilian Portuguese and Hindi. If you read in German, Arabic or Korean, the comparison ends here: NaturalReader covers 90+ languages.
Where the audio is made, and what that means for your documents
NaturalReader's high-quality AI voices are generated on its servers; offline listening works by exporting the rendered audio as MP3 first, which the free tier cannot do at all. For a lot of reading that is fine. For contracts, medical letters, unpublished manuscripts, internal specs and anything under NDA, it means the text has been sent somewhere.
Sandbook never sends it. Files are copied into the app's own sandbox, speech is synthesized locally through Apple MLX, and scanned pages are recognized on the device. There is no account, no ads and no tracking, and your books, text and voices stay on your phone.
Where NaturalReader is plainly better
- Languages and voices. 200+ voices across 90+ languages, against 41 voices in six languages.
- Formats. Word, PowerPoint, images and cloud-drive files, on top of PDF, TXT and DRM-free EPUB. Sandbook has no DOCX or PowerPoint import.
- More than one screen. A web app and a Chrome extension alongside the mobile app, covered by the same subscription, with an optional free account to sync across them.
- Listening with the screen off. Its release notes describe background playback for the reading queue. Sandbook's real-time reading pauses when the screen locks; only a chapter prepared ahead of time plays locked.
Where Sandbook is better
It is free with nothing held back, it works with no connection at all — including for text it has never seen before — and it asks for no identity. It also treats PDFs more carefully than most readers: visual line breaks are rejoined and hyphenated words stitched back together before speech, so a paper reads as continuous prose rather than stopping every nine words. Books get word-by-word highlighting, tap-a-paragraph-to-read, auto-advance between chapters, per-book voice and speed, and they open where you stopped. And its camera scanning is free, where NaturalReader keeps OCR on its paid plans.
Before you install, you can hear Sandbook's voices in a browser tab with the same text you would give NaturalReader.
Compare
| Sandbook | NaturalReader | |
|---|---|---|
| Price | Free. No in-app purchase, no subscription, no daily cap. | Free: Unlimited listening on the device's own system voices, then 20,000 characters a day on Lite voices and 4,000 shared characters a day on Plus and Cloned voices. No MP3 export and no OCR. Paid, on the vendor website: Lite $13.90/month or $79/year, Plus $20.90/month or $119/year, Pro $25.90/month or $159/year. The US iOS App Store still carries the entry tier's old name and lower prices — Premium Plan at $9.99/month or $59.99/year — while Plus and Pro match the web exactly. |
| Where speech is generated | On your iPhone or iPad, on the GPU. | The AI voices are generated on NaturalReader's servers; the Free Voices tier uses the device's own pre-installed system voices. |
| Works offline | Yes, completely, including synthesis. | Offline listening means exporting the rendered audio as MP3 first; generating new speech needs a connection. |
| Account required | No sign-in screen at all. | No — you can start listening without one. A free account adds cross-device sync. |
| Voices | 41, all bundled and free, one quality tier. | 200+ AI voices, tiered Lite / Plus / Pro / Cloned. |
| Languages | 6: US and UK English (28 voices), Spanish, French, Italian, Brazilian Portuguese and Hindi. 41 voices in all. | 90+ across the AI voices. |
| Listening with the screen locked | Only a chapter prepared ahead of time. Real-time reading pauses when the screen locks. | Yes — the release notes describe background playback for the reading queue. Release notes for v9.43, 13 June 2026: “Improved Reading Queue background playback.” |
| Formats | EPUB, PDF, TXT, RTF, Markdown, HTML, web pages, camera scans and photos, typed or pasted text. No DOCX. | PDF, Word (.doc/.docx), PowerPoint, Pages, Numbers, RTF, TXT, DRM-free EPUB, images, and files from Google Drive, Dropbox and OneDrive. |
| Platforms | iPhone and iPad. iOS 18.2 or later; iPhone 12 or later, or an iPad with an A14 or M1 chip or later. | iPhone and iPad on iOS 16.4 or later, and Apple Vision on visionOS 1.0 or later. A subscription also covers the web app and the Chrome extension. |
| Audio export | M4A, from the Reader tab (typed or pasted text). No whole-book export. | MP3, on paid plans only — 1 million characters a month on Lite voices. Free Voices can never be exported. |
| OCR / scanning | Camera scans and photos, recognized on the device. Image-only PDF files are not recognized. | Yes, on paid plans — the free tier explicitly excludes it. |
| Privacy | Books, text and voices stay on the device and are never uploaded. No account, no ads, no tracking. | Data Used to Track You: Identifiers (Device ID). Data Not Linked to You: Purchases (Purchase History), Identifiers (Device ID) and Usage Data (Product Interaction), for Analytics and Product Personalization. |
Free offline alternatives to NaturalReader on iPhone, ranked
Apps that cost nothing to use in some real form and generate their speech on the phone rather than on a server. Sandbook publishes this list, so it is labelled.
Sandbook(the app this site is about)
Free with no in-app purchase and no cap: all 41 Kokoro-82M voices (28 in US and UK English, plus Spanish, French, Italian, Brazilian Portuguese and Hindi) from first launch; EPUB, PDF, web pages and camera scans with word-by-word highlighting; no account. Real-time reading pauses when the screen locks (prepared chapters play locked), it has 6 voice languages, fewer than some multilingual readers, and no DOCX, iCloud sync or whole-book export.
Free with no In-App Purchases row on its listing, reading PDF, EPUB, DOCX, web pages and camera scans in 31 languages, and its own site says the audio is generated on your device. It never names the speech engine.
EPUB and PDF turned into audiobooks with word-level read-along, background playback and a sleep timer, on a choice of three on-device engines. Free covers three books and three voices; the rest is $4.99/month or $33.99/year.
Already on the phone, free, and on-device once an Enhanced Quality voice has downloaded — worth trying before installing anything. It reads what is on screen: no library, no EPUB or PDF importer, and no reading position kept per file.
Ranked on four things in this order: what it costs with nothing held back, whether speech is generated on the device with no connection, voice quality, and what the app does with a book once it is open. Only apps whose own pages establish both the price and the on-device synthesis are listed.
Questions about switching from NaturalReader
Is Sandbook a full NaturalReader alternative?
Only if you read in English, Spanish, French, Italian, Brazilian Portuguese or Hindi on an iPhone or iPad. It matches NaturalReader on the core job, turning a document into a natural voice, and beats it on price and privacy. It does not have NaturalReader's 90+ languages, Word or PowerPoint support, a web app or browser extension, or continuous reading with the screen off.
NaturalReader's free tier already exists. Why switch?
NaturalReader's free tier meters the good voices by characters, not by time. Unlimited listening on the device's own system voices, then 20,000 characters a day on Lite voices and 4,000 shared characters a day on Plus and Cloned voices. No MP3 export and no OCR. That is fine for a page and thin for a book. Sandbook's 41 voices have no daily allowance and no tiering, and they run without a connection. The trade is language coverage and format support, both of which NaturalReader wins.
Does Sandbook read Word documents?
No. It reads EPUB, PDF, TXT, RTF, Markdown and HTML files, web pages, camera scans and photos, and text you type or paste. DOCX, PowerPoint, MOBI and AZW3 are not supported. Copying the text and pasting it into the Reader tab works if you only need it once.
Can I export a chapter as audio?
Only text in the Reader tab, as an M4A file through the share sheet. There is no whole-book export, so an EPUB or PDF you imported can be listened to but not saved as an audio file. You can prepare a chapter's audio to listen with the screen locked, inside the app.
How we compared
Every figure on this page comes from NaturalReader’s own public pages — the listing on the US App Store, the pricing page and the privacy policy — read on 14 September 2026. Prices, limits and features change without notice: where this page and the other app disagree, believe the other app.
Sandbook publishes this comparison, so read it as our argument rather than a neutral review. Everything in the Sandbook column is what the app does today, and you can check all of it in the app itself.
Sources
NaturalReader's website and its iOS listing price the entry tier differently and call it by different names. Both are listed here.
- NaturalReader Help Centre — Plans & Pricing (Personal Version), updated 13 August 2026 · checked 14 September 2026
- NaturalReader Help Centre — Voices, Languages, and TTS Limits (Personal Version), updated 13 July 2026 · checked 14 September 2026
- NaturalReader - Text To Speech — US App Store listing (v9.46) · checked 14 September 2026
Try it alongside NaturalReader
If your reading is multilingual, full of scans and Word files, or spread across a browser and a phone, NaturalReader is built for that and Sandbook is not. If it is books and PDFs in English or one of Sandbook's five other voice languages, on an iPhone, and you would rather they were never uploaded or billed by the character, this NaturalReader alternative is free and runs entirely on your device.
iOS 18.2 or later · iPhone 12 or later & iPad