Okular

Overview

Okular is a document viewer for people who move between PDFs, ebooks, comics, images and other formats. Its broad coverage, annotation tools and PDF signing make it a capable everyday reader; the lack of OCR rules it out for workflows that need text recognized from scans.

Released under the GPLv2+, Okular is free software with source code available through KDE's GitLab repository. KDE's site announces version 26.08, released on 20 August 2026, and accepts donations through PayPal and other methods.

Key features

Reading and annotating

Okular handles PDF, EPUB, DjVu, PostScript, TIFF, DVI, XPS, FictionBook, Plucker and fax files, as well as Markdown, images and CBR or CBZ comics. That breadth suits readers who want one application for mixed documents and media rather than a PDF-only tool. It can also fill forms and read text aloud.

Selection tools copy text, areas and tables, and a magnifier enlarges small text. Annotation mode adds inline or popup notes, highlights, underlines and text. These tools make Okular useful for reviewing and working with documents, not just viewing them. It does not support OCR, so scanned pages that need text recognition call for another tool.

PDF signatures

Okular can sign PDFs, verify signatures and detect document modifications. That combination is useful for handling signed files and checking whether they have changed, while keeping the application focused on document work rather than OCR.

Privacy and sustainability

KDE says its software does not transmit information from users' devices without explicit action; where telemetry is offered, it is opt-in and disabled by default. Okular also received the Blue Angel ecolabel in 2022 for resource and energy efficiency. These are meaningful considerations for privacy- and resource-conscious users.

Pricing

Okular's Free Software plan costs nothing under the GPLv2+. There is no paid tier to weigh against it, so the full application is the straightforward choice for individuals and organizations that want a free, open-source viewer. Users can also donate to KDE, but donations are optional.

Platforms

Okular runs on Linux, Windows and macOS, with support also extending to BSD. Linux users can install it through distribution software stores or Flatpak on Flathub; the Microsoft Store is the recommended Windows source. Untested nightly builds are offered for Windows and macOS on ARM and Intel, so users who prioritize stable releases should prefer the regular installation routes.

Installations can include separate modules for particular formats and interface translations. Removing the application does not remove data viewed, created or modified with it. Support and development communication take place through a mailing list, IRC, Matrix, a forum and KDE's bug tracker.

Who it's for

Okular is a strong fit for readers, students and document reviewers who need a free viewer across desktop platforms and value annotations, form filling, text-to-speech or PDF signature checks. Its format range is especially useful when reading tasks include ebooks, comics, images or Markdown alongside PDFs. Choose another tool if OCR is essential.

Pros and cons

• Broad format coverage: Handles common documents alongside ebooks, comics, images and Markdown, reducing the need for separate viewers.
• Useful document tools: Annotations, selection, form filling and text-to-speech support more than passive reading.
• PDF signature handling: Can sign and verify signatures and detect modifications.
• Free and open-source: The GPLv2+ license and cross-platform support make it accessible across Linux, Windows and macOS.
• No OCR: Scanned documents that require text recognition need another application.
• Installation varies by platform: Users need to choose a route suited to their operating system, and nightly builds are explicitly untested.

Alternatives

For a different free option with broad platform support, ViewAnyFile.app is available on Android, iOS, Linux, macOS, the web and Windows. XnConvert may suit readers focused on image conversion; it is free for private, educational and non-profit use, with paid company licensing. Geeqie is another free GPLv2 image-viewing option.

HFSExplorer is a free GPLv3 alternative. nomacs is free for private and commercial use under GPLv3. Universal File Opener offers a free plan and a trial on Android and Windows, with file-size and compatibility limits applying to its free plan. Evince is a free Linux alternative. FastStone Image Viewer may be worth considering for Windows users comparing personal-use and commercial licensing.

Browse more options in File Viewer Software or PDF Readers.

Verdict

Choose Okular if you want a free, open-source desktop viewer that combines wide format support with annotation and PDF signature tools. Its main weakness is decisive for some readers: it cannot perform OCR, so scanned-document recognition requires a separate solution.