PDF Ultra vs Athene Reader
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
PDF Ultra
Effortlessly read, listen to, and annotate PDFs on your iPhone and iPad. Enjoy a focused, ad-free experience with features like natural read-aloud, full-text search, and in-document markup. Your files stay private and offline.
- Natural read-aloud with background audio
- Full-text search and in-page highlighting
- Pen, highlighter, and eraser tools
- Multiple reading modes (Day, Night, Sepia)
- Offline functionality and privacy-focused design
- Continuous and single-page scrolling
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PDF Ultra is a fast, elegant PDF reader for iPhone and iPad — built to make reading, listening to, and marking up documents feel effortless. It runs entirely on your device: no ads, no accounts, no tracking, and nothing ever leaves your iPhone. Whether you're studying a textbook, reviewing a report, or catching up on long documents hands-free, PDF Ultra keeps everything calm, focused, and beautifully native. READ YOUR WAY Day, Night and Sepia reading modes Continuous or single-page, vertical or horizontal scrolling Pinch and double-tap zoom, with a default zoom you choose Immersive reading mode and gentle auto-scroll Remembers your last page, reading progress and time LISTEN TO ANY PDF Natural read-aloud with true background audio Lock screen and Control Center playback controls Follow-along highlighting as each sentence is read Adjustable speed and voice, with auto-advance between pages Picks up exactly where you left off — even after relaunch FIND ANYTHING INSTANTLY Full-text search across the entire document Live results with match counts and next / previous In-page highlighting and recent-search history MARK IT UP Pen, highlighter and eraser with color palettes Undo, redo and clear Ink saves right into the PDF — and stays removable STAY ORGANIZED Library with Continue Reading, Favorites and All Files Sort by name, date or size Bookmarks and a tap-to-jump table of contents Open PDFs straight from Files, Mail, Safari and more Opens password-protected PDFs MADE FOR IPHONE & IPAD Universal, edge-to-edge layout with a roomy iPad sidebar Light, Dark and System themes with seven accent colors PRIVATE BY DESIGN PDF Ultra works fully offline. Your files stay on your device — there are no accounts to create and no data collection. Just open a PDF and start reading. No ads. No tracking.
Athene Reader
Organize and read your personal book collection, including EPUB, PDF, and MOBI formats. Features include customizable reading settings, note-taking, drawing on pages, and an AI-powered assistant for context-aware questions. Listen to your books with a natural-sounding text-to-speech engine.
- Import EPUB, PDF, MOBI, and more
- Customizable reading experience
- Highlighting and note-taking
- Drawing and markup on PDFs
- AI-powered page assistant
- Text-to-speech for audiobooks
- Calibre server integration
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Athene is a reader for the books you already own. Bring your books from Files, from Mail, from your computer over Wi‑Fi, from a link, or from anywhere that can share a file, and they go on a shelf that looks like one. EPUB and PDF open as they are; MOBI, AZW3, Word, FB2, TXT and HTML files become books as they arrive. The Athene Bookstore has free classics from Project Gutenberg and Standard Ebooks and, in the US, DRM-free books to buy. If you keep your library on a calibre server, Athene browses that shelf too, from + in your Library — on your home network, or from anywhere through your own VPN such as Tailscale. THE PAGE Open a book and the app steps back. Just the page, on white, sepia or night paper, or paper in any colour you like, in the typeface and size you read best, including any Google Font. Highlight a passage, add a note, drop a bookmark, and find them all again under Marks. Select a passage in another language to translate it. The shelf itself follows the time of day — Morning, Sunset, Night — or stays on the one you pick. NOTES YOU CAN DRAW Type a note in the margin, or sketch in it. On a PDF, mark up the page itself with Apple Pencil. THE NOTEBOOK Every highlight, note and drawing from every book you read, in one place, with filters and search. Write what stayed with you after a chapter, a reading session or a whole book, typed or drawn; your reflections stay even if the book leaves your shelf. LISTEN Any book, read aloud in a warm, natural voice that runs entirely on your device, and keeps reading with the screen locked. PDFs too: Listen skips the running heads, page numbers and footnotes, reads scanned pages, and describes the pictures and tables as it reaches them. The voice is a one-time download of about 242 MB. A DICTIONARY Select a word to see what it means and how to say it. It is built in, and it works offline. ASK THE PAGE Tap the owl while you read and ask about what is in front of you. Who is she again? What did that word mean? What just happened? The Owl answers from the pages around where you are — this chapter at most, never the whole book, never your other books — and if the pages do not say, it tells you that instead of guessing. YOUR MODEL, YOUR CHOICE On a device with Apple Intelligence, the Owl thinks on the device and nothing you ask is sent anywhere. Or point it at your own Ollama server on your own network. Or bring a key from Claude, OpenRouter or OpenAI. Athene asks before the first question leaves the device, names the address it would send to, and remembers your answer. ON EVERY DEVICE Turn on iCloud Sync and your place, highlights, notes, drawings, collections and reading settings follow you between your iPhone and iPad. It goes only to your own private iCloud, and what you wrote is encrypted on your device first. With a calibre server, highlights go both ways: yours to your calibre library, and the ones you make in calibre's own reader to Athene. With KOReader on an e-reader, your books, your place, and your highlights, notes and bookmarks stay in step through a sync server of your own. PRIVATE BY CONSTRUCTION Athene has no account and no analytics, and nothing about you goes to the developer. Your books, your notes and your questions stay on your device or go only where you have pointed them. The privacy policy says the same, in plain words. FREE Reading is free. No account, no subscription, no limit: the shelf, the reader, Listen, the dictionary, the Owl, the Notebook, iCloud Sync, calibre and KOReader, your highlights and notes. Nothing is locked. WHAT READERS SAY “The app works perfectly with my Calibre library.” (ZenoNow) “I’d happily pay for Athene if it weren’t free.” (Momji_iphone) Athene requires iOS 26. The on-device Owl requires Apple Intelligence (iPhone 15 Pro and later, M-series iPad, iPad mini A17 Pro); on other devices the Owl works with your own Ollama server or an API key. Pictures in PDFs are described on iOS 27 with Apple Intelligence.
Screenshots
Verdict
The clearest difference is review sentiment: Athene Reader at 92% against PDF Ultra's 0%. Athene Reader also leads on price (Free vs $1.99) and rating (4.7 vs 4.3). PDF Ultra's advantage is iOS requirement (17.0 vs 26.0). On ads, in-app purchases and device support there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Athene Reader is free to download; PDF Ultra costs $1.99 up front. Neither carries in-app purchases, so what you see is what you pay.
Athene Reader holds the better App Store score, 4.7 against 4.3. That said, the two scores are not equally well evidenced: Athene Reader has 15 ratings behind it against 3, so its average is the more settled of the two. Written reviews point the same way: 0% of PDF Ultra's written reviews are positive against 92% of Athene Reader's.
| Parameter | PDF Ultra | Athene Reader |
|---|---|---|
| Price | $1.99 | Free — better |
| Rating | 4.3 (3 ratings) | 4.7 (15 ratings) — better |
| Positive reviews | 0.0% of reviews | 92.3% of reviews — better |
| Number of ratings | 3 | 15 — better |
| Update frequency | — | Daily |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Paid | Free — better |
| Devices | iPhone, iPad, Mac — better | iPhone, iPad |
| Requires iOS | 17.0 — better | 26.0 |
| Further details — not scored | ||
| Size | 6 MB | 61 MB |
| Age rating | 4+ | 4+ |
| Developer | Ram Tulugu | Aditya Sreedhar |
Customer experience
PDF Ultra
Athene Reader
In-app purchases
PDF Ultra
No in-app purchases
Athene Reader
No in-app purchases









