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.

Navigating around an e-book ¶

You can “turn pages” in a book by either:

Clicking in the left or right margin or the page with the mouse

Pressing the spacebar, page up, page down or arrow keys

On a touchscreen tapping on the text or swiping left and right

You can access the viewer controls by either:

Right clicking on the text

Pressing the Esc or Menu keys

On a touchscreen by tapping the top 1/3rd of the screen

The viewer has two modes, “paged” and “flow”. In paged mode the book content is presented as pages, similar to a paper book. In flow mode the text is presented continuously, like in a web browser. You can switch between them using the viewer Preferences under Page layout or by pressing the Ctrl+M key.

Bookmarks¶

When you are in the middle of a book and close the E-book viewer, it will remember where you stopped reading and return there the next time you open the book. You can also set bookmarks in the book by using the Bookmarks button in the E-book viewer controls or pressing Ctrl+B. When viewing EPUB format books, these bookmarks are actually saved in the EPUB file itself. You can add bookmarks, then send the file to a friend. When they open the file, they will be able to see your bookmarks. You can turn off this behavior in the Miscellaneous section of the viewer preferences.

Table of Contents¶

If the book you are reading defines a Table of Contents, you can access it by pressing the Table of Contents button. This will bring up a list of sections in the book. You can click on any of them to jump to that portion of the book.

Navigating by location¶

E-books, unlike paper books, have no concept of pages. You can refer to precise locations in e-books using the Go to → Location functionality in the viewer controls.

You can use this location information to unambiguously refer to parts of the books when discussing it with friends or referring to it in other works. You can enter these locations under Go to → Location in the viewer controls.

There is a URL you can copy to the clipboard and paste into other programs or documents. Clicking on this URL will open the book in the calibre E-book viewer at the current location.

If you click on links inside the e-book to take you to different parts of the book, such as an endnote, you can use the Back and Forward buttons in the top left corner of the viewer controls. These buttons behave just like those in a web browser.

Reference mode¶

calibre also has a very handy Reference mode. You can turn it on by clicking the Reference mode button in the viewer controls. Once you do this, every paragraph will have a unique number displayed at the start, made up of the section and paragraph numbers.

You can use this number to unambiguously refer to parts of the books when discussing it with friends or referring to it in other works. You can enter these numbers in the Go to function to navigate to a particular reference location.

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’s in browser viewer, you can have the viewer sync its annotations with the browser viewer by going to Preferences → Miscellaneous 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 or sentence being currently read is highlighted. Speech is synthesized from the text using either the Piper neural text-to-speech engine or your operating system services for text-to-speech. You can change the backend and 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.

Note

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.

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:

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 Peña. If you select the Case sensitive box then accents, spaces and punctuation are no longer ignored.
Whole words - Searches for whole words. So for example, the search pena will match the word Peña but not the word Penal. As with Contains searches above, accents and punctuation are ignored unless the Case sensitive box is checked.
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.
Regex - Interprets the search text as a regular expression. To learn more about using regular expressions, see the tutorial.

Following links using only the keyboard ¶

The E-book viewer has a Hints mode that allows you to click links in the text without using the mouse. Press the Alt+F key and all links in the current screen will be highlighted with a number or letter over them. Press the letter on your keyboard to click the link. Pressing the Esc key will abort the Hints mode without selecting any link.

If more than thirty five links are on-screen then some of them will have multiple letters, in which case type the first and second, or the first and press Enter to activate. You can also use the Backspace key to undo a mistake in typing.

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.

Syncing with a paper edition of the current book ¶

Some e-books, that have corresponding print editions, include metadata that marks the start of each paper page. For such e-books, the viewer allows you to jump to a particular paper edition page via the Go to button in the viewer controls. You can also optionally display the paper page corresponding to the current location in the book’s headers or footers via the viewer settings, by adding Pages from paper edition to either the header or the footer.

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 E-book viewer¶
Keyboard shortcut	Action
`Home, Ctrl+ArrowUp, Ctrl+ArrowLeft`	Scroll to the start of the current file in a multi file book
`Ctrl+Home`	Scroll to the beginning of the book
`Ctrl+End`	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
`ArrowUp`	Scroll backwards, smoothly in flow mode and by screen fulls in paged mode
`ArrowDown`	Scroll forwards, smoothly in flow mode and by screen fulls in paged mode
`ArrowLeft`	Scroll leftwards by a little in flow mode and by a page in paged mode
`ArrowRight`	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
`Ctrl+PageUp`	Scroll to the previous section
`Ctrl+PageDown`	Scroll to the next section
`Alt+ArrowLeft`	Back
`Alt+ArrowRight`	Forward
`Ctrl+T`	Toggle Table of Contents
`Ctrl+S`	Read aloud
`Alt+P`	Change settings quickly by creating and switching to profiles
`Alt+f`	Follow links with the keyboard
`Ctrl+C`	Copy to clipboard
`Alt+C`	Copy current location to clipboard
`Ctrl+Shift+C`	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
`Ctrl+0`	Restore default font size
`Ctrl+]`	Increase number of pages per screen
`Ctrl+[`	Decrease number of pages per screen
`Ctrl+Alt+C`	Make number of pages per screen automatic
`F11, Ctrl+Shift+F`	Toggle full screen
`Ctrl+M`	Toggle between Paged mode and Flow mode for text layout
`Ctrl+W`	Toggle the scrollbar
`Ctrl+X`	Toggle the Reference mode
`Ctrl+B`	Show/hide bookmarks
`Ctrl+Alt+B`	New bookmark
`Ctrl+N, Ctrl+E`	Show the book metadata
`Ctrl+Alt+F5, Ctrl+Alt+R`	Reload book
`Ctrl+Shift+ArrowRight`	Alter the current selection forward by a word
`Ctrl+Shift+ArrowLeft`	Alter the current selection backwards by a word
`Shift+ArrowRight`	Alter the current selection forward by a character
`Shift+ArrowLeft`	Alter the current selection backwards by a character
`Shift+ArrowDown`	Alter the current selection forward by a line
`Shift+Home`	Extend the current selection to the start of the line
`Shift+End`	Extend the current selection to the end of the line
`Ctrl+A`	Select all
`Shift+ArrowUp`	Alter the current selection backwards by a line
`Ctrl+Shift+ArrowDown`	Alter the current selection forward by a paragraph
`Ctrl+Shift+ArrowUp`	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
`Ctrl+Spacebar`	Toggle auto-scroll
`Alt+ArrowUp`	Auto scroll faster
`Alt+ArrowDown`	Auto scroll slower
`Ctrl+I`	Show/hide Inspector
`Ctrl+L`	Show/hide the word lookup panel
`Ctrl+Q (Cmd+Q on macOS)`	Quit
`Ctrl+P`	Print book to PDF
`Ctrl+F11`	Toggle the toolbar
`Ctrl+H`	Toggle the highlights panel
`Ctrl+D`	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 E-book viewer ¶

The calibre E-book 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:

body.calibre-viewer-dark-colors: Set when using a dark color scheme
body.calibre-viewer-light-colors: Set when using a light color scheme
body.calibre-viewer-paginated: Set when in paged mode
body.calibre-viewer-scrolling: Set when in flow (non-paginated) mode
body.calibre-footnote-container: Set when displaying a popup footnote

Finally, you can use the calibre color scheme colors via CSS variables. The calibre E-book 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.