A modern calibre for people who love ebooks

Everything calibre does, with less in the way

calibre-zen is calibre with a calm, modern window. Your books, devices and plugins work just as they always have.

A clean look, in light, dim or dark

Every button, menu and icon shares one style, so the window is easy to scan. Pick light, dim or dark and one of six colour schemes, and it changes right away.

Filters you can read at a glance

The tag browser is now a simple list of filters. Each row shows how many books match, and a tick marks what is on.

See a book before you open it

The book you pick sits at the top with its cover, details and the buttons you use most. Below it, switch between a table and a grid of covers.

A reader that opens at once

Books open in about a tenth of a second. Change the text size and the reading theme from one small menu.

Your library on every device

Share your books with phones, tablets and other computers in the house. Close the window and sharing keeps going from the menubar or the tray.

Move over from calibre in one click

The welcome wizard brings your library, plugins and settings across. Your calibre stays exactly as it was.

Made for people who love their ebooks

• Longtime calibre users. Keep every feature you rely on, in a window that feels calm to use every day.
• New readers. Get started without learning a busy interface first. Three short pages show you around.
• People who find busy screens tiring. One spacing, one style and fewer buttons leave more room for your books.
• Families and homes with many devices. Share one library with every phone, tablet and e-reader in the house.
• Home server fans. Run your library in Docker and read from any browser, with a login and a folder that adds new books.

What readers say

Why people pick it

• It is still calibre. Every feature and every plugin is there. Each new calibre release is merged in, about once a month.
• Your calibre stays untouched. It installs as a separate app, so both can sit side by side and open at once.
• Free and open source. No account, no ads and no tracking. The code is on GitHub under the same licence as calibre.
• Change your mind any time. Turn off any new part you do not like, and calibre’s own version comes back.
• It keeps itself up to date. New versions download and install from inside the app.
• Works on your computer. Windows, macOS on Apple silicon and Intel, Linux, and Docker for a home server.

Questions

Is it free? Yes, completely. It is open source, with no account and no tracking.

Will it change my calibre or my library? No. It is a separate app with its own settings. Both apps can open the same library, one at a time.

Do my plugins still work? Yes. It runs plugins just like calibre does, and the Plugins page lists the ones we have checked.

Can I bring over my calibre settings? Yes. The welcome wizard copies your library, plugins and preferences in one click.

Can I get calibre’s old look back? Yes, one part at a time. The menu under the app’s icon turns off any new part on the next start.

Which computers does it run on? Windows, macOS on Apple silicon and Intel, and Linux on x86_64 and arm64. A Docker image runs it on a home server.

More answers are in the FAQ.

Give your library a calmer home

It is free, and your calibre stays just as it is. Download it and open your library in a minute.

0.4.1, share with the window closed

calibre-zen 0.4.1 is out, on calibre 9.15. If you have 0.4.0, the update window offers it for you. The Download button on this page picks out the file for your computer.

Highlights

• Close the window and your library stays shared, from the menubar or the tray.
• Restart in headless mode, in the Preferences menu, switches to it.
• The window comes back from the icon whenever you want it.

Share with the window closed shows how it works. Every change is in the 0.4.1 release notes.

0.4.0, your library on a home server

calibre-zen 0.4.0 is out, on calibre 9.15.

Highlights

• A Docker image that shares your library with every browser in the house.
• An optional login, and a folder that adds every book you drop in it.
• Sharing that keeps working when several people read at once.

Run it on a home server has the command. Every change is in the 0.4.0 release notes.

0.3.0, a reader that opens at once

calibre-zen 0.3.0 is out, on calibre 9.15. If you have 0.2.0, the update window offers it for you. The Download button on this page picks out the file for your computer.

Highlights

• Books open in about a tenth of a second, because a reader is ready and waiting.
• The reader has the new look, in light and dark.
• A header and a footer over the page, like Apple Books.
• Themes & Settings changes the text size and the reading theme in one place.
• Buttons for the next page and chapter, and a bar you drag to jump through the book.
• The contents show the book’s cover and title, and mark the chapter you are reading.

Every change, with screenshots and the details behind them, is in the 0.3.0 release notes.

0.2.0, a calmer editor and an easy move from calibre

calibre-zen 0.2.0 is out, now on calibre 9.15. The Download button on this page picks out the file for your computer.

Highlights

• Updates download and install from inside the app, starting with the next release.
• Bring over your calibre library, plugins and settings from the welcome wizard.
• A smaller Edit metadata window with tabs and grouped fields.
• Stars you click, a calendar in your theme, and double-click to edit a cell.
• A Cover shape choice in the grid, Uniform or Natural.
• A Flatpak and a one-line install for Linux.

Every change, with screenshots and the details behind them, is in the 0.2.0 release notes.

0.1.0, the first release

calibre-zen 0.1.0 is out, on calibre 9.14.0, for Windows, macOS and Linux. The Download button on this page picks out the file for your computer; Getting around is the short tour of what moved.

In the box

• A Windows installer that upgrades itself, a portable build that keeps its library in its own folder, and a zip.
• A signed and notarized macOS disk image for Apple silicon and Intel.
• Linux archives for x86_64 and arm64.
• An update check that watches calibre-zen’s own releases, so the status bar says when the next one is out.
• A welcome that walks through the three things that moved, with a recording of each.

A macOS public preview of calibre-zen

calibre-zen now has an identity of its own. You can download and try it on your own. Your existing library and settings are untouched, and both apps can be open at once.

The parts a stylesheet cannot reach

Custom widgets are calibre-zen’s own components, added on top of calibre much like a plugin would be. calibre’s tag browser, book list, cover grid and status bar draw themselves, so a theme can never reach them. These sit in front of them instead, and everything they do underneath is still calibre’s.

Each one can be turned off on its own, and nothing about calibre itself changes. That is the foundation for the better components coming next.

Improvements

• The tag browser’s tree replaced with a filter panel: one screenful of rows at a time, counts beside each value, and a Reset that clears the lot
• The centre split in two, a preview of the selected book above the list, with the search bar and a Grid/Table switcher in the strip between them
• The book list rebuilt around a composite Details column on tall row cards, while sorting, inline editing, column resizing and the header menu stay calibre’s own
• Three cover-grid densities, and every cover cropped to one shape so a shelf has a straight edge rather than a ragged one
• A status bar that reports what is happening behind your back: the current library, the sort, whether the content server is sharing and on which port, and any job still running
• Every piece switchable: CALIBRE_ZEN_FILTERS=0, CALIBRE_ZEN_CENTRE=0 and CALIBRE_ZEN_STATUS=0 each give calibre’s own back

Consistent icons, typography and themes

The numbers all come from one place. A colour ramp, a radius scale, a type scale and a single density sit behind the whole stylesheet, so a button, a menu row, a text field and a tab agree on their padding, their corner and their weight instead of each having been drawn on its own day. Variants sit on top of that, which means a primary button and a destructive one differ because their intent differs, not because they were styled apart.

Icons follow the same rule. Every one of calibre’s top-level icons is redrawn as a line glyph and inked in the palette colour at paint time, so nothing is a small colour photograph sitting next to a label. An unmapped name falls through to calibre’s own icon, so a pack is never required to be complete.

Improvements

• One token set behind the sheet: colour ramp, radius scale, type scale, density
• All 179 of calibre’s top-level icons redrawn as line glyphs, rendered from SVG in the palette colour and re-inked whenever the palette changes
• Inter for the interface, Literata for anything being read, both bundled so the app looks the same on every machine
• Menus, buttons, fields and tabs share one padding and one corner radius, with primary and destructive variants where intent differs
• Six colour schemes, and a switcher for match system, light, dim or dark, both on the toolbar and both applied without a restart
• Chevrons in place of Qt’s arrow triangles, and a rounded window behind every rounded popup

Why I forked calibre

calibre is the best library manager there is, and it looks like it was designed in 2008, because it was.

I have used calibre for years and it is genuinely powerful. But the onboarding is rough and the interface is inconsistent enough that simple things feel hard. Buttons that look the same behave differently. Spacing changes from one panel to the next. I have OCD and ADHD, and the more I used calibre the more that inconsistency pulled my attention away from what I was actually trying to do.

I do not mean this unkindly. calibre is Kovid’s labour of love and it does more than any other tool in its category. I had let this idea go several times before, because the answer was always the same: it is old Qt, that is just how it is. But it kept bothering me, so I opened the codebase to see how far I could get.

I mostly build web applications and I am not a Qt expert. What I do have is a sense of how to model an interface and move around one. I used AI to throw together some cheap prototypes, pulled theme tokens from shadcn and Tailwind, and built a consistent layer first, so every button, label, menu and icon shares the same padding and sizing. Then I added variants so each one can match its intent. Once that held up, I spent a weekend getting it into a state other people could try.

I hope you find it useful.

Key decisions

• Everything is built around themes and variants, so the fork touches form and not functionality
• Custom widgets use composition and stay modular, which makes pulling upstream changes much easier
• The restyling lives in an overlay package that patches calibre from the outside instead of editing it, so upstream stays pullable and any part of it can be switched off with an environment variable

Improvements

• A full palette and stylesheet, with six colour schemes and a light, dim and dark switcher
• Every top-level icon redrawn as a line glyph, inked in the palette colour
• Inter and Literata bundled, so the interface reads the same on every machine
• The tag browser tree replaced with a filter panel
• Primary and destructive button variants, rounded popups, chevrons instead of triangles