Comparison

The Ebook Converter vs Calibre Sync

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

Head to head
About

The Ebook Converter

Easily convert ebooks between numerous formats like EPUB, MOBI, and PDF. Simply select your file, choose an output format, and convert in seconds. Save, share, or open converted files in your preferred reader apps.

Highlights
  • Convert between major ebook formats
  • Supports EPUB, MOBI, PDF, TXT, AZW3, and more
  • Fast conversion in seconds
  • Save, share, or open converted files
  • In-app file browser
  • Cloud and local conversion options
Features
Read full description

Easily convert your ebooks between nearly any major formats! 1. Select your input file 2. Choose your output format ( MOBI, EPUB, PDF, TXT, AZW3 etc. ) 3. Convert! It will only take a few seconds. 4. Save your file, or open it in your favorite app! Choose from any of these output formats: MOBI, EPUB, TCR, PDB, PDF, AZW3, LRF, FB2, LIT, TXT, RTF, OEB You can convert from dozens of input formats, here are some of the most popular formats we support converting your ebooks from: EPUB, MOBI, PDF, TXT, FB2, DOCX, AZW3, ZIP, DOC, HTML and more! Save, Share or Open your converted ebooks in your favorite reader apps immediately. You can even browse your previously converted files with our in-app file browser. Conversions usually take less than 15 seconds! Conversion is done on a secure cloud server, which makes conversion easier, faster and much more battery-friendly. You must have an internet connection to use this app. Files are immediately deleted from the server after conversion. While the files are immediately deleted after conversion or cancellation, you should be aware that by using this app, you agree that your files will be sent over to internet from the app to the conversion server. We've also recently added support for local conversions for many popular conversion types. These conversions don't require a server, and are usually done almost instantly! We are continuing to add support for more local conversions with each update. This app includes an optional auto-renewable subscription (Premium Pass): Premium Pass beings with a free trial period, then an auto-renewable monthly subscription when trial ends. Payment will be charged to your Apple account at confirmation of purchase and will automatically renew (at the duration/price selected) unless auto-renew is turned off at least 24 hrs before the end of the current period. Account will be charged for renewal within 24-hours prior to the end of the current period. Current subscription may not be cancelled during the active subscription period; however, you can manage your subscription and/or turn off auto-renewal by visiting your Apple Account Settings after purchase. Any unused portion of the free initial period will be forfeited when you purchase a subscription. Privacy Policy: https://float.support/the-ebook-converter/privacy Terms of Use: https://float.support/the-ebook-converter/terms

About

Calibre Sync

Access and manage your Calibre ebook libraries from your mobile device. Sync with popular cloud services or connect wirelessly to your desktop Calibre. Browse, search, download, and organize your collection.

Highlights
  • Access Calibre libraries from cloud services
  • Wireless connection to Calibre desktop
  • Browse, sort, and search books
  • Download books to your device
  • Support for multiple libraries and accounts
  • Send books to Kindle
  • Customizable book list layouts
Features
Read full description

Lifetime support, no extra charge, no subscription fee. Calibre Sync can: - help you access full Calibre libraries on most popular personal cloud services, including Google Drive, Dropbox, Microsoft OneDrive, Box, pCloud, MEGA, iCloud, WebDav, Nextcloud, OwnCloud, and TeraBox - simply the most supported for cloud services. - transform your device to a smart device emulator that connects to Calibre wirelessly. It even supports Calibre libraries on your external storage and from Calibre Content Server or Calibre-web with amazing performance. Move your Calibre libraries to your favourite cloud providers and access those libraries via Calibre Sync to browse, sort, search, download and read books on your device. Calibre Sync also supports multiple libraries across multiple Drive, Dropbox, OneDrive, Box, pCloud, MEGA, iCloud, WebDav, Nextcloud, OwnCloud, and TeraBox accounts simultaneously. Features: - Unlimited Calibre libraries - Wireless connect to Calibre effortlessly as Smart device - Easy switch between multiple libraries across multiple accounts - Automatic check and update libraries when launching the app - Pull, Refresh or Remove a library from Calibre Sync - Support different book list layouts: List - detailed and simple, Grid, and Carousel - View your library statistics - Send books to Kindle with ease - Search across all of your available libraries - Search books by title, authors, and even in comments and custom columns - Filter books on authors, series, tags, language, publishers, formats and in custom columns - Sort libraries by title, author, ratings, and several Date options - ascending and descending - Filter downloaded books - Configuration for each library download location - Support for custom columns in book details view - Quick access to book download and share via slideable list view - Zoom the book cover - Support "swipe from book to book" in book details view - Email or share a copy of downloaded book - Open downloaded book in your book reader application to read a book - View the file size of each book format - Show book identifiers and link to source (like ISBN, Amazon, Google Books, Goodreads, etc) - Dark/light themes - And many more features... To move your Calibre library to cloud services: 1) Open Calibre on your Laptop/PC/Desktop 2) Select "Switch/create library..." from the Calibre menu 3) Select an empty folder on your Cloud drive in "New Location" drop down 4) Select "Move current library to new location", then press OK 5) Wait for cloud sync to complete. 6) Then you are ready to use Calibre Sync. To move your Calibre library to your phone storage, just copy the library directory to your phone storage. Notes: - Calibre Sync is not a reader app. You must install and use one of the many excellent reader apps available. - Only Microsoft OneDrive for Personal accounts (shared) are supported. Please email us if you observe any inconsistencies. - Due to restriction in Box API, Calibre Sync must acquire write permission in order to download files, download is not a read action on Box. Calibre Sync guarantees that it will not perform any write actions against your data in Box cloud account. - Calibre Sync use WebDav API of Nextcloud and OwnCloud services, and it requires case sensitive file system to work properly. Therefore, you must make sure that your libraries are set up on case sensitive file system (Linux, recent MacOS, Windows NTFS with case sensitive enabled). Please leave your reviews and suggestions to help us improve the app. For more information see https://calibresync.bitbucket.io Calibre is © Kovid Goyal - calibre-ebook.com Drive is © Google LLC. Dropbox is © Dropbox inc. OneDrive is © Microsoft Box is © Box inc. pCloud is © pCloud AG Nextcloud is © Nextcloud GmbH OwnCloud is © OwnCloud MEGA is © MEGA iCloud is © Apple Inc TeraBox © Flextech Inc

Screenshots

The Ebook Converter4 screens
Calibre Sync4 screens

Verdict

The call

The clearest difference is price: The Ebook Converter at Free against Calibre Sync's $4.99. The Ebook Converter also leads on rating (4.5 vs 3.9) and ratings volume (2.5K vs 55). Calibre Sync's advantage is in-app purchases (none vs 5) and review sentiment (62% vs 31%). On ads, device support and iOS requirement 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

CostPrice · In-app purchases · Ads · Monetization

The Ebook Converter is free to download; Calibre Sync costs $4.99 up front. The Ebook Converter sells 5 in-app purchases, starting at $0.99 per month. Calibre Sync asks for nothing beyond the download.

ReceptionRating · Positive reviews · Number of ratings

The Ebook Converter holds the better App Store score, 4.5 against 3.9. That said, the two scores are not equally well evidenced: The Ebook Converter has 2.5K ratings behind it against 55, so its average is the more settled of the two. Written reviews complicate that: 31% of The Ebook Converter's written reviews are positive against 62% of Calibre Sync's, so the app with the better star average is not the one people write more warmly about.

UpkeepUpdate frequency

The Ebook Converter ships an update every 3 months, Calibre Sync weekly. The most recent releases landed on November 6, 2026 and November 7, 2026 respectively.

Scorecard7 real differences · 3 level
The Ebook Converter versus Calibre Sync: the parameters behind the verdict, then further details
ParameterThe Ebook ConverterCalibre Sync
PriceFree — better$4.99
Rating4.5 (2.5K ratings) — better3.9 (55 ratings)
Positive reviews31.0% of reviews61.8% of reviews — better
Number of ratings2.5K — better55
Update frequencyEvery 3 monthsWeekly — better
AdsNoNo
In-app purchasesYesNo — better
MonetizationFreemium — betterPaid
DevicesiPhone, iPad, iPodiPhone, iPad, iPod
Requires iOS15.615.0 — better
Further details — not scored
Size46 MB128 MB
Age rating4+4+
DeveloperFloat Tech, LLCDUONG THUY PHAM

Customer experience

The Ebook Converter

All ratings2,471 ratings
Positive87.3%
Neutral1.9%
Negative10.8%
Written reviews336 reviews
Positive31.0%
Neutral3.9%
Negative65.2%

Calibre Sync

All ratings55 ratings
Positive70.9%
Neutral9.1%
Negative20.0%
Written reviews89 reviews
Positive61.8%
Neutral6.7%
Negative31.5%

User reviews

The Ebook Converter

From 2.5K App Store ratings

What we love

  • 👍 Easy to use
  • 🚀 Fast conversion
  • 💡 Useful for converting ebooks
  • 😊 Great app

Room to improve

  • 🐛 Conversion issues
  • 🔒 Requires subscription for full functionality
  • 💰 Not free
  • 🤔 Misleading description

Calibre Sync

From 55 App Store ratings

What we love

  • 👍 Access Calibre library anywhere
  • 🚀 Syncs easily and quickly
  • 💡 Mirrors Calibre library design
  • 💡 Viewable and searchable library
  • 💡 Downloadable on demand

Room to improve

  • 🐛 Popup cannot be removed
  • 🐛 Sync issues with Calibre v9
  • 🐛 Developer non-responsive
  • 🐛 App broken since Calibre v9
  • 🐛 Deprecated database columns

Bugs and requests

The Ebook Converter

Reported bugs

3 issues
  • Conversion failures
  • Corrupted output files
  • Compatibility issues with certain devices

Requested features

3 requests
  • Support for more file formats
  • Batch conversion option
  • Ability to rename converted files

Calibre Sync

Reported bugs

29 issues
  • Popup reappears every launch
  • Calibre version 9 bricked the app
  • Database error
  • Stopped working since Calibre update
  • Error when changing DB
Show 24 more
  • Mega integration does not connect
  • Sync issues with Calibre v9
  • App broken since Calibre v9
  • Deprecated database columns
  • Stopped working recently
  • No longer compatible with Calibre v9
  • Sync fails
  • Failed to download metadata
  • Cannot connect to server
  • Does not work with Dropbox
  • Highlights not saved in PDF
  • Syncing new books stopped
  • Cannot use preferred mail app
  • Cannot automatically send to Kindle
  • Cannot launch preferred app from this app
  • Unable to read most book covers
  • Horrible file finding
  • Does not work on iPad after update
  • App won't find files on local storage
  • Failed to download metadata from Nutstore
  • Cannot connect to server at all
  • Cannot sync Calibre to iPad
  • WebDAV not working
  • SMB not working

Requested features

18 requests
  • More customizability with viewing options
  • Integrated ebook reader
  • Mark books as favorites
  • Calendar feature for reading
  • Use configured mail app
Show 13 more
  • Option for 'automatically send to Kindle'
  • Set preferred reading apps by type
  • Launch preferred app from this app
  • AI services for translation and text-to-speech
  • Display bookshelves
  • Update FAQ and provide YouTube tutorial
  • iCloud integration
  • Support for more cloud services
  • Ability to add book directly to cloud library
  • Mark books as read/unread and sync back
  • Support for multiple libraries
  • Local storage accessible via Files app
  • Virtual view explanation

In-app purchases

5 purchases

The Ebook Converter

Subscriptions2
  • Premium Pass$0.991 Month
  • Premium Pass7 Days trial$3.991 Month
One-time3
  • Lifetime Pass$9.99
  • Lifetime Pass$19.99
  • Lifetime Pass Promo$29.99
None

Calibre Sync

No in-app purchases

Questions

Is The Ebook Converter free?
The Ebook Converter is free to download, with in-app purchases available.
Is Calibre Sync free?
Calibre Sync costs $4.99, with no in-app purchases.
Which has better reviews, The Ebook Converter or Calibre Sync?
The Ebook Converter is rated higher. The Ebook Converter averages 4.5 out of 5 from 2.5K ratings, while Calibre Sync averages 3.9 from 55 ratings.
Do The Ebook Converter or Calibre Sync have ads?
Neither The Ebook Converter nor Calibre Sync shows ads.
Which is updated more often, The Ebook Converter or Calibre Sync?
The Ebook Converter ships an update every 3 months, and Calibre Sync weekly. Most recently, The Ebook Converter was updated on November 6, 2026 and Calibre Sync on November 7, 2026.

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