How to Sync Calibre to iPhone & iPad

Quick answer: There is no Calibre app for iPhone or iPad, so syncing means connecting an iOS reader to the Calibre library on your computer. The cleanest method is Calibre's Content Server: start it on your desktop, connect your iOS reader to http://<your-ip>:8080, and download your books. Most methods only copy books one way. A reader with two-way Calibre sync also writes your reading progress, ratings, and stats back to Calibre.

Calibre is the best free way to organize an ebook library, but it runs only on Windows, macOS, and Linux. To read that library on an iPhone or iPad you connect an iOS app to Calibre, rather than running Calibre on the device. This guide covers every working method in 2026, which ones keep your reading progress in sync, and the one cloud setup that can quietly corrupt your library.

One-way copy vs two-way sync

The word "sync" hides an important difference. Almost every method below only copies books from Calibre to your phone. Your reading progress, ratings, and finished dates then live on the phone and never make it back to Calibre. True two-way sync, where the app writes your progress and ratings back into Calibre, is rare. If you read the same books across devices, it is the feature worth looking for.

Method 1: Calibre Content Server (the reliable core)

Calibre has a built-in server that publishes your whole library over your network:

1. Open Calibre, click Connect/share, and choose Start Content Server.
2. Note your computer's local IP address. Your library is now at http://<your-ip>:8080, with an OPDS feed at http://<your-ip>:8080/opds.
3. On your iPhone or iPad, connect your reader app to that address.

This is the method Calibre's own documentation points iOS users to. It is reliable and free, with one condition: Calibre has to stay open and running on the computer. For the full walkthrough, including authentication and remote access, see Calibre Content Server on iPhone and iPad.

Method 2: Cloud folder (convenient, with one real risk)

You can keep your books in a cloud folder (iCloud Drive, Dropbox, or OneDrive) and open them on iOS without keeping a computer running. A reader that browses cloud storage shows your books and downloads them on demand.

There is a serious caveat, straight from Calibre's own FAQ: do not put your Calibre library on Google Drive, which can cause data loss, and be careful with any cloud service. The danger is that the cloud client and Calibre both write to the library database (metadata.db) at the same time and corrupt it. The safe pattern is to close Calibre fully and let the cloud finish syncing before you open the library on another device. This method is read-only from the phone's side: nothing you do on iOS writes back to Calibre.

Method 3: Two-way Calibre sync

If you want your phone and computer to agree on where you are in every book, you need an app that syncs both directions over the Content Server. justRead does this: it connects to your Calibre Content Server (with Wi-Fi auto-discovery and HTTP Digest authentication), imports your books with covers and metadata intact, and then writes your reading progress, star ratings, want-to-read flags, finished dates, session counts, and reading statistics back to Calibre. It also pulls your ratings and custom columns in.

Because it talks to Calibre's running server rather than a shared database file, it sidesteps the cloud corruption risk entirely. Status badges (New, Changed, Synced) and a "Select New & Changed" option keep repeat syncs fast, and a post-sync log shows exactly what changed per book. The full workflow is on the Calibre sync page.

What about Calibre Companion and the old apps?

If you search the App Store you will still find Calibre Companion, but it has not been updated since 2020 and sits behind a subscription, so treat it as abandoned. The same is true of several once-popular readers: KyBook 3 has not been updated since 2019, and Marvin was pulled from the App Store. For a current option, see our Calibre alternative for iOS guide.

Common problems

• The library will not load. Confirm Calibre is open, the Content Server is running, both devices are on the same network, and the IP and port are right.
• Books appear but progress does not sync. Most methods are one-way. Only a reader with explicit two-way Calibre sync writes progress back.
• My library got corrupted. This is almost always the cloud-folder issue. Never let a cloud service sync metadata.db while Calibre is open, and never use Google Drive for the library.
• Some books will not open. DRM-protected Kindle files cannot be opened by Calibre or any third-party iOS reader. Only DRM-free EPUB and PDF files work.

The short version

To read your Calibre library on iOS, connect a reader to the Content Server for reliability, or a cloud folder for convenience, and pick two-way sync if you want progress to follow you across devices. For the catalog side of this, the OPDS reader overview covers connecting to Calibre and self-hosted servers alike.

Download justRead on the App Store to sync your Calibre library both ways.