The E-book viewer¶

calibre includes a built-in E-book viewer that can view all the major e-book formats. The E-book viewer is highly customizable and has many advanced features.

Starting the E-book viewer¶

You can view any of the books in your calibre library by selecting the book and pressing the View button. This will open up the book in the E-book viewer. You can also launch the E-book viewer by itself from the Start menu in Windows. On macOS, you can pin it to the dock and launch it from there. On Linux you can use its launcher in the desktop menus or run the command ebook-viewer.

Highlighting text¶

When you select text in the viewer, a little popup bar appears next to the selection. You can click the highlight button in that bar to create a highlight. You can add notes and change the color of the highlight. On a touch screen, long tap a word to select it and show the popup bar. Once in highlight mode you can change what text is selected, using touch screen friendly selection handles. Drag the handles to the top or bottom margins to scroll while selecting. You can also Shift+click or right click to extend the selection, particularly useful for multi-page selections.

You can use the Highlights button in the viewer controls to show a separate panel with a list of all highlights in the book, sorted by chapter.

You can browse all highlights in your entire calibre library by right clicking the View button and choosing Browse annotations.

Finally, if you use the calibre Content server‚Äôs in browser viewer, you can have the viewer sync its annotations with the browser viewer by going to Preferences‚ÄČ‚Üí‚ÄČMiscellaneous in the viewer preferences and entering the username of the Content server viewer to sync with. Use the special value * to sync with anonymous users.

Read aloud¶

The viewer can read book text aloud. To use it you can simply click the Read aloud button in the viewer controls to start reading book text aloud. The word being currently read is highlighted. Speech is synthesized from the text using your operating system services for text-to-speech. You can change the voice being used by clicking the gear icon in the bar that is displayed while Read aloud is active.

You can also read aloud highlighted passages by adding the Read aloud button to the selection bar in the viewer preferences under Selection behavior.


Support for text-to-speech in browsers is very incomplete and bug-ridden so how well Read aloud will work in the in-browser viewer is dependent on how well the underlying browser supports text-to-speech. In particular, highlighting of current word does not work, and changing speed or voice will cause reading to start again from the beginning.


On Linux, Read aloud requires Speech Dispatcher to be installed and working.


On Windows, not all installed voices may be visible to the SAPI sub-system that is used for text-to-speech. There are instructions to make all voices visible.

Searching the text¶

The viewer has very powerful search capabilities. Press the Ctrl+F key or access the viewer controls and click search. The simplest form of searching is to just search for whatever text you enter in the text box. The different forms of searching are chosen by the search mode box below the search input. Available modes are:

  1. Contains - The simplest default mode. The text entered in the search box is searched for anywhere. All punctuation, accents and spaces are ignored. For example, the search: Pena will match all of the following: penal, pen a, pen.a and Pe√Īa. If you select the Case sensitive box then accents, spaces and punctuation are no longer ignored.

  2. Whole words - Searches for whole words. So for example, the search pena will match the word Pe√Īa but not the word Penal. As with Contains searches above, accents and punctuation are ignored unless the Case sensitive box is checked.

  3. Nearby words - Searches for whole words that are near each other. So for example, the search calibre cool will match places where the words calibre and cool occur within sixty characters of each other. To change the number of characters add the new number to the end of the list of words. For instance, calibre cool awesome 120 will match places where the three words occur within 120 characters of each other. Note that punctuation and accents are not ignored for these searches.

  4. Regex - Interprets the search text as a regular expression. To learn more about using regular expressions, see the tutorial.

Customizing the look and feel of your reading experience¶

You can change font sizes on the fly by using Font size in the viewer controls or Ctrl++ or Ctrl+- or holding the Ctrl key and using the mouse wheel.

Colors can be changed in the Colors section of the viewer preferences.

You can change the number of pages displayed on the screen as well as page margins in Page layout in the viewer preferences.

You can display custom headers and footers such as time left to read, current chapter title, book position, etc. via the Headers and footers section of the viewer preferences.

More advanced customization can be achieved by the Styles settings. Here you can specify a background image to display under the text and also a stylesheet you can set that will be applied to every book. Using it you can do things like change paragraph styles, text justification, etc. For examples of custom stylesheets used by calibre’s users, see the forums.

Dictionary lookup¶

You can look up the meaning of words in the current book by double clicking or long tapping the word you want to lookup and then clicking the lookup button that looks like a library.

Copying text and images¶

You can select text and images by dragging the content with your mouse and then right clicking and selecting Copy to copy to the clipboard. The copied material can be pasted into another application as plain text and images.

Zooming in on images¶

You can zoom in to show an image at full size in a separate window by either double clicking or long tapping on it. You can also right click on it and choose View image.

Keyboard shortcuts¶

The viewer has extensive keyboard shortcuts, like the rest of calibre. They can be customised in the viewer Preferences. The default shortcuts are listed below:

Keyboard shortcuts for the calibre viewer¶

Keyboard shortcut


Home, Ctrl+ArrowUp, Ctrl+ArrowLeft

Scroll to the start of the current file in a multi file book


Scroll to the beginning of the book


Scroll to the end of the book

End, Ctrl+ArrowDown, Ctrl+ArrowRight

Scroll to the end of the current file in a multi file book


Scroll backwards, smoothly in flow mode and by screen fulls in paged mode


Scroll forwards, smoothly in flow mode and by screen fulls in paged mode


Scroll leftwards by a little in flow mode and by a page in paged mode


Scroll rightwards by a little in flow mode and by a page in paged mode

PageUp, Shift+Spacebar

Scroll backwards by screen-fulls

PageDown, Spacebar

Scroll forwards by screen-fulls


Scroll to the previous section


Scroll to the next section






Toggle Table of Contents


Read aloud


Change settings quickly by creating and switching to profiles


Follow links with the keyboard


Copy to clipboard


Copy current location to clipboard


Copy current location as calibre:// URL to clipboard

/, Ctrl+f, Cmd+f

Start search

F3, Enter

Find next

Shift+F3, Shift+Enter

Find previous

Ctrl+Plus, Meta+Plus

Increase font size

Ctrl+Minus, Meta+Minus

Decrease font size


Restore default font size


Increase number of pages per screen


Decrease number of pages per screen


Make number of pages per screen automatic

F11, Ctrl+Shift+F

Toggle full screen


Toggle between Paged mode and Flow mode for text layout


Toggle the scrollbar


Toggle the Reference mode


Show/hide bookmarks


New bookmark

Ctrl+N, Ctrl+E

Show the book metadata

Ctrl+Alt+F5, Ctrl+Alt+R

Reload book


Alter the current selection forward by a word


Alter the current selection backwards by a word


Alter the current selection forward by a character


Alter the current selection backwards by a character


Alter the current selection forward by a line


Extend the current selection to the start of the line


Extend the current selection to the end of the line


Select all


Alter the current selection backwards by a line


Alter the current selection forward by a paragraph


Alter the current selection backwards by a paragraph

Esc, MenuKey

Show the E-book viewer controls

Ctrl+Comma, Ctrl+Esc, Meta+Esc, Meta+Comma

Show E-book viewer preferences

Ctrl+G, ;, :

Go to a specified book location or position


Toggle auto-scroll


Auto scroll faster


Auto scroll slower


Show/hide Inspector


Show/hide the word lookup panel

Ctrl+Q (Cmd+Q on macOS)



Print book to PDF


Toggle the toolbar


Toggle the highlights panel


Edit this book

Non re-flowable content¶

Some books have very wide content that cannot be broken up at page boundaries. For example tables or <pre> tags. In such cases, you should switch the viewer to flow mode by pressing Ctrl+M to read this content. Alternately, you can also add the following CSS to the Styles section of the viewer preferences to force the viewer to break up lines of text in <pre> tags:

code, pre { white-space: pre-wrap }

Designing your book to work well with the calibre viewer¶

The calibre viewer will set the is-calibre-viewer class on the root element. So you can write CSS rules that apply only for it. Additionally, the viewer will set the following classes on the body element:


Set when using a dark color scheme


Set when using a light color scheme


Set when in paged mode


Set when in flow (non-paginated) mode


Set when displaying a popup footnote

Finally, you can use the calibre color scheme colors via CSS variables. The calibre viewer defines the following variables: --calibre-viewer-background-color, --calibre-viewer-foreground-color and optionally --calibre-viewer-link-color in color themes that define a link color.