Comparison

Lu Reader vs Chaeksum

Price, ratings, monetisation and update history for both apps, side by side β€” with what reviewers say about each.

Head to head
About

Lu Reader

This application offers a streamlined reading experience for various document and e-book formats, including EPUB and PDF. It features customizable reading settings, text-to-speech functionality, and smart library management. Users can back up their data to Google Drive.

Highlights
  • Supports EPUB, PDF, TXT, DOC, FB2, HWP, ZIP, CBZ
  • 11 customizable color themes
  • Adjustable font size, line spacing, and margins
  • In-app brightness control
  • Text-to-speech with adjustable speed
  • Automatic table of contents generation
  • Smart library with sorting and search
Features
Read full description

Lu Reader is a fast, clean, all-in-one reader for your documents and e-books - with no clutter and no sign-up required. SUPPORTED FORMATS - Text and e-books: TXT, EPUB, PDF, FB2, DOC, DOCX, HWP, HWPX - Archives containing text files: ZIP, CBZ COMFORTABLE READING - 11 color themes (cream, sepia, mint, black, navy and more) - Fine-tune font size, line spacing and margins - In-app brightness control for reading in the dark - Keep-screen-on, screen rotation and immersive full-screen mode VOICE READING (TTS) - Listen to any text with the current sentence highlighted - Adjustable speed from 0.6x to 2.0x - Choose from voices installed on your device - Sleep timer to stop automatically AUTOMATIC TABLE OF CONTENTS - Builds a chapter list even for plain TXT files - Detects multilingual chapter patterns - Jumps to and highlights the current chapter SMART LIBRARY - Add files from the Files app or the in-app file browser - Reading progress percentage and progress bar - Sort by name, date or progress, and search by filename - Bookmark your position; select a word for dictionary and translation - Auto-scroll and in-text search BACKUP & RESTORE - Safely back up your books, reading positions, bookmarks and settings to your own Google Drive - Restore everything on a new device Lu Reader keeps the focus on reading. Download it and enjoy your library, your way.

About

Chaeksum

Features
Read full description

Chaeksum is a reading app with no ads. The name is Korean for "the breath of a book". No banners, no pop-ups, no video ads. When you read, there is only text. Made for people who loved e-ink readers and now read on their phone. Easy on the eyes β€’ The page is never brighter than the room around you, with less flicker in the dark β€’ Warm grey paper without blue glare, warmer after sunset β€’ Black & white mode for this app only β€’ Turn page by page with your choice of effect, or scroll straight down (trial) β€’ The screen stays on while you read, and brightness is right there in the reader Any file, fast β€’ TXT, EPUB and PDF β€” password-protected PDFs too β€’ Import a ZIP of books in one go β€’ EPUBs keep their own table of contents and footnotes β€’ Even books thousands of pages long open in about a second β€’ Link your Downloads folder once and new books appear right away β€’ Find, sort and rename books in your library β€’ On iPad in landscape, two pages side by side like a book β€” PDFs too, with contents and search While you read β€’ Highlights, notes, bookmarks and full-text search; step through matches with β€Ή β€Ί β€’ Long-press to select, drag the handles, and carry on onto the next page β€’ Share a passage as a paper card image β€’ Dictionary and translation β€’ Read aloud with natural voices and a sleep timer (10 free minutes a day) β€’ Turn pages with a keyboard or a Bluetooth page turner β€’ Choose what the page header and footer show: title, chapter, pages left, time left, percent, progress bar β€’ Home Screen and Lock Screen widgets, plus today's reading time and your streak β€’ Lock the app with Face ID β€’ Export highlights and notes as text β€’ Literata, Charter and Korean book fonts β€” remembered separately for Korean and English books β€’ English, Korean and Japanese Chaeksum Pro β€” buy once, keep forever (not a subscription) β€’ Fine typesetting: line and paragraph spacing, letter spacing, margins, weight, alignment β€’ Different fonts, spacing and margins per book; save your own presets β€’ Unlimited read-aloud β€’ Unlimited highlights and notes (free: unlimited in your first book, then 3 per book) β€’ Add your own fonts (.ttf, .otf) β€’ Every paper tone β€’ iPhone–iPad sync through your own iCloud: position, highlights, notes, bookmarks and book files (no sign-up) Books bought from stores with DRM protection can't be opened. Chaeksum reads the TXT, EPUB and PDF files you own. Tips The app is made without ads. If you like it, you can buy the developer a coffee in Settings. Tips unlock nothing β€” they are just support.

Screenshots

Lu Reader4 screens
Chaeksum4 screens

Verdict

The call

The clearest difference is in-app purchases: Lu Reader at none against Chaeksum's 4. Lu Reader also leads on iOS requirement (15.5 vs 17.4). Chaeksum's advantage is ads (none vs shown). On price, update cadence and device support there is nothing between them.

Scored on Price Β· Rating Β· Positive reviews Β· Number of ratings Β· Update frequency Β· Ads Β· In-app purchases Β· Monetization Β· Best chart rank Β· Devices Β· Requires iOS

CostPrice Β· In-app purchases Β· Ads Β· Monetization

Both are free to download. Chaeksum sells 4 one-off in-app purchases. Lu Reader asks for nothing beyond the download.

UpkeepUpdate frequency

Lu Reader ships an update every 4 days, Chaeksum every 3 days. The most recent releases landed on October 7, 2026 and October 17, 2026 respectively.

Scorecard3 real differences Β· 5 level
Lu Reader versus Chaeksum: the parameters behind the verdict, then further details
ParameterLu ReaderChaeksum
PriceFreeFree
Positive reviews100.0% of reviewsβ€”
Update frequencyEvery 4 daysEvery 3 days β€” better
AdsYesNo β€” better
In-app purchasesNo β€” betterYes
MonetizationAd-supportedβ€”
DevicesiPhone, iPodiPhone, iPad
Requires iOS15.5 β€” better17.4
Further details β€” not scored
Size95 MB38 MB
Age rating4+4+
Developersanghun jeongJAEBAEK LEE

In-app purchases

None

Lu Reader

No in-app purchases

4 purchases

Chaeksum

One-time4
  • Tip Β· A Coffee$0.49
  • Chaeksum Pro$1.99
  • Tip Β· Tea and Dessert$1.99
Show 1 more
  • Tip Β· A Book$6.99

Questions

Is Lu Reader free?
Lu Reader is free to download, with no in-app purchases.
Is Chaeksum free?
Chaeksum is free to download, with in-app purchases available.
Do Lu Reader or Chaeksum have ads?
Lu Reader shows ads; Chaeksum does not.
Which is updated more often, Lu Reader or Chaeksum?
Lu Reader ships an update every 4 days, and Chaeksum every 3 days. Most recently, Lu Reader was updated on October 7, 2026 and Chaeksum on October 17, 2026.

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