Originally published at: https://www.onlyoffice.com/blog/2022/12/best-open-source-pdf-readers/
Nowadays everyone who has to deal with electronic documents needs a PDF reader due to the popularity and widespread distribution of this format. In this article, you will find a brief overview of the best open source PDF readers so that you can choose one for your work or personal use on different platforms.
Why you need an open source PDF viewer
First of all, let’s be clear on that the phrases “PDF reader” and “PDF viewer” mean the same sort of thing and can be used as synonyms. It’s an application that allows you to open PDF files on your device and view their content. They can also be able to perform some other basic operations, like adding annotations and saving PDFs to other formats, but they don’t usually allow you to change or modify information in your files.
In many cases, a PDF reader is all you need to work with PDF files. You don’t need to install complex PDF editing tools if you just open files for viewing and save documents to PDF for printing.
In our list, you will find some of the best open source tools that you can use to view the content of PDF files. In comparison with proprietary software, open source PDF readers offer the same features but are more reliable and transparent. They are also often free of charge, which allows you to do other things with your money.
1. ONLYOFFICE
Image source: www.onlyoffice.com
ONLYOFFICE is a very interesting option if you are looking for an open source PDF viewer. It’s a full-featured collaborative office suite that can handle office documents of different types and PDF files.
You can use the ONLYOFFICE suite to create and edit text documents, spreadsheets, presentations and fillable forms as well as open and view PDFs. The built-in viewing tool makes it possible to navigate through the pages of PDF files using a thumbnail pane with page previews.
Also, there is a navigation pane that allows you to easily access the required page of your file with a few clicks. Using the Select tool, you can copy text and graphical objects, and the Hand tool allows you to browse the entire PDF document.
The ONLYOFFICE open source PDF viewer also offers such features as downloading, printing and zoom settings. If you have to read PDFs at night, you can switch to Dark Mode.
The ONLYOFFICE suite can be used as a file converter. You can open a PDF file and convert it to another format. For example, you can turn your PDFs into editable DOCX files. Other compatible formats include ODT, TXT, DOTX, OTT, RTF, HTML, FB2 and EPUB.
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Pros:
- Suitable for all kinds of office documents, including PDFs
- Available on all popular platforms — web, desktop, mobile
- Powerful format conversion features
- Dark Mode
Cons:
- Opening large PDF files sometimes takes long
- No PDF annotation support
2. Sumatra PDF
Image source: www.sumatrapdfreader.org
Sumatra PDF is a free and open source PDF viewer that is compatible with many document formats, including MOBI, EPUB, XPS, DjVu, CHM, and comic book formats — CBZ and CBR. The application is available only on Windows and runs on some older versions, like Windows Vista and Windows XP.
The main advantage of Sumatra PDF is the simplicity of its user interface. It’s equipped with the most essential features for a better reading experience and allows you to instantly access the recently opened files.
Sumatra PDF offers a portable version that can be used from an external USB drive, so you don’t even have to install the app.
The program supports a lot of hotkey commands to make working with PDFs even easier and is very good at opening large PDF files.
Pros:
- Simple user interface
- Portable version
- Fast performance
- Hotkey commands
Cons:
- No clients for Linux and macOS
3. Okular
Image source: okular.kde.org
Okular is a multi-platform open source PDF viewer that comes as part of the KDF software package. It’s designed for viewing PDF documents, comic books and e-books, browsing images and even opening Markdown documents.
Okular offers an advanced user interface, allowing you to add annotations and notes, select text and make it bigger with the Magnifier Mode, and leave bookmarks. The built-in Thumbnails panel makes navigation much easier, and the Content panel lets you access the required chapter with a few clicks.
Unlike other open source PDF readers, Okular offers the ability to view and verify digital signatures. Another advantage is that you can digitally sign PDFs yourself.
Being part of the of the KDE project, the app seamlessly works on a great number of Linux distros. There are also versions for Windows and macOS. When it comes to Windows, Okular is available only in the Microsoft Store.
Pros:
- Advanced user interface
- Support of e-signatures
- Available on all popular OS
- Compatible with a variety of formats
Cons:
- Comparatively high system requirements
4. Evince
Image source: wiki.gnome.org/Apps/Evince
Evince is a free and open source PDF reader that is compatible with multiple document formats. Apart from the Portable Document Format, it works with DjVu, PS, TIFF and XPS files and opens comic books — CB7, CBR, CBT and CBZ.
The app is a lightweight reader that covers the most essential functions, and its aim is to replace different document viewers that exist within the GNOME Desktop with one program.
Evince comes with a minimalistic interface and allows you to open, browse and print PDF files with ease. It makes navigation convenient due to the Drag&Drop feature and supports basic search functionality. Leaving annotations is also possible.
The viewer is available only on Linux and offers a lot of installation options so that Linux users can easily install it on their favourite distro.
Pros:
- Simple and intuitive user interface
- Various installation options
- Compatible with a variety of formats
Cons:
- No clients for Windows and macOS
- Opening large PDF files sometimes takes long
5. Xournal++
Image source: xournalpp.github.io
Xournal++ is not a usual PDF viewer. It’s an open source and cross-platform app for taking notes with PDF annotation support. That means that you can use this tool as a PDF reader with handwriting notetaking features.
The app is compatible with pressure-sensitive stylus and drawing tablets, so you can open your PDFs and create complex notes. You are allowed to keep track of your notes by using page previews.
Xournal++ has a built-in LaTeX editor, which allows you to create differential equations or electrical circuits on the pages of your PDF files. This feature is really useful if you need a PDF viewer for scientific and research purposes.
The app is highly customizable so you can create a unique toolbar layout. PDF export is another feature supported by the app.
Pros:
- Rich notetaking functionality
- Available on Windows, Linux and macOS
- Handwriting recognition
- Built-in LaTeX editor
Cons:
- User interface might look overloaded
How to choose the best open source PDF reader
Taking into consideration the fact that there are a lot of PDF viewing tools that perform the same operations but in different ways, sometimes it might be difficult to choose the ideal application. Your choice depends on your preferences. Opt for:
- ONLYOFFICE if you need a comprehensive office suite for your OS with PDF viewing functionality
- Sumatra PDF if you run Windows and need a simple PDF reader with intuitive interface elements
- Okular if you happen to digitally sign PDFs
- Evince if you are a Linux enthusiast
- Xournal++ if you have to annotate PDF files very often