What Is Sumatra PDF

Sumatra PDF is a free, lightweight Windows document reader built by Krzysztof Kowalczyk. It is fully open source, with no ads and no bundled third party software, and it opens fast while using very little memory. Beyond PDF, it reads EPUB, MOBI, CBZ and CBR comics, DjVu, XPS, CHM, and common image formats. Sumatra PDF runs only on Windows, and it ships in 32 bit, 64 bit, and ARM64 builds, plus an installer free portable edition.

If your machine is already weighed down by programs that eat hundreds of megabytes, and you just want a reader that opens a file the moment you click it, Sumatra PDF fits. For a broader look at similar tools, see Best Free PDF Tools and Office Alternatives for Windows in 2026. It does not demand much from the hardware, so old laptops and office PCs handle it fine, whether you need it for a one off emergency or for daily reading. Unlike software that greets you with ads and quietly offers to install a browser toolbar, Sumatra PDF opens straight to the document and wastes no time.

Key Features

  • Multi format reading. It opens PDF, EPUB, MOBI, CBZ, CBR, DjVu, XPS, CHM, and images, so one program covers what used to take several readers.
  • Speed and lightness. The installer is about 10 MB, and both startup and opening large files happen almost instantly, even on older machines.
  • Portable mode. A ZIP portable build runs from a USB drive on any Windows PC without installation.
  • Deep customization. Shortcuts, themes, and the toolbar layout can all be reshaped to taste, which pays off once the habits settle in.
  • LaTeX inverse search. Paired with a TeX editor, you can double click the PDF to jump back to the source, a feature writers of papers and typeset documents appreciate.
  • Annotations and forms. Recent versions let you fill PDF forms, add notes, and sign.
  • Reading aids. It supports text to speech, in document search, bookmarks, and table of contents navigation.

How to Install

  1. Open the official download page at https://www.sumatrapdfreader.org/download-free-pdf-viewer.html.
  2. On a normal PC, grab the 64 bit installer. If you would rather not install anything, choose the 64 bit portable ZIP, which runs after extraction.
  3. Double click the installer and follow the wizard. It asks whether to associate PDF and other formats during setup.
  4. For the portable build, unzip the archive to any folder (for example D:\Tools\SumatraPDF) and run SumatraPDF.exe.

When downloading, check that the filename says 64 bit. The 32 bit build still runs on a modern PC, but it cannot use the memory addressing of a 64 bit system, so large files open a little slower. The ARM64 build is for Qualcomm based devices like some Surface models. Regular Intel or AMD computers should use the 64 bit version.

How to Use It

  1. Open files. Double click a PDF, or press Ctrl + O inside Sumatra PDF to pick a file.
  2. Navigate. Scroll with the mouse wheel or arrow keys to turn pages, Ctrl + wheel to zoom, and Ctrl + K to open the command palette.
  3. Set as default. In Options, make Sumatra PDF the default PDF reader so a double click opens it from anywhere.
  4. Search text. Press Ctrl + F to search the current document, or Ctrl + Shift + F to search across documents.
  5. Use it portably. Copy the portable folder to a USB drive and run it on any PC. Reading progress is saved alongside the config, so it travels with the drive.

When you read a 40 page product manual, jump to the right chapter through the table of contents, then hit Ctrl + F for a keyword. That beats flipping pages by eye. To compare two contracts, put the windows side by side and run Ctrl + Shift + F to see where the same clause shows up across files. The text to speech feature is handy for listening to a document on a commute, though the voice is the mechanical system default, and long passages get tiring on the ears.

Things to Watch

  • Platform limit. Windows only. There is no macOS or Linux build.
  • Safe sources. Get the stable or pre release builds only from sumatrapdfreader.org, and avoid bundled downloads from unknown places.
  • Pre releases. A Pre-release carries the newest features but may be unstable, so production use should stick with the stable version.
  • Format focus. Although it reads many formats, PDF reading is the core. Heavy PDF editing is not its strength.
  • Compatibility. Very old systems, such as Windows XP, should stay on older builds like 3.1.2.

Installers from third party download sites are the real trap. Many slip in their own promoted programs alongside the real one. Trust the single domain sumatrapdfreader.org and you spare yourself the later chore of uninstalling junk. The pre release build suits people who want new features early, but when the file matters, a contract or a submitted assignment, the stable version is the safer bet.

Download

  • Official download https://www.sumatrapdfreader.org/download-free-pdf-viewer.html

Official Site

  • https://www.sumatrapdfreader.org/

Getting Started

When you first install Sumatra PDF, do not rush to tweak every setting. Memorize the common paths, confirm that a double clicked PDF opens correctly, and the basic setup is done. I suggest installing the 64 bit build and letting it take over PDF associations. Contracts, manuals, and scans then open with a double click, which is far more comfortable than squinting at them inside a browser tab.

If you hop between machines, say between the office, home, and a print shop, the portable build is the easier choice. Unzip it to a USB drive, plug in, and it runs. Half finished reading progress rides along with the config, so pulling the drive does not lose your place. For an EPUB novel or a MOBI ebook on the commute, one program covers what used to need several readers.

Spend two minutes mapping the shortcuts to your hand. Ctrl + O to open, Ctrl + F to search, Ctrl + wheel to zoom. Once they are muscle memory, long documents move faster. For side by side comparison, put two documents on two screens and use Ctrl + Shift + F to find where the same sentence appears across files.

Themes and toolbar layout can change too, but a newcomer should get the reading flow smooth in the first week before fussing with looks. When the default interface starts to annoy you, go into Options and adjust at leisure.

FAQ

Can Sumatra PDF edit PDF content? It reads well and edits poorly. Recent versions fill forms, add notes, and sign, but rearranging pages, changing text, and merging or splitting are not its strengths. For serious editing you need a more dedicated tool, or the PDF options listed in that software roundup.

Do the portable and installed builds work the same? The core features are identical. The difference is only in how they install. The portable build writes no registry entries and sets no system associations, which suits a USB drive or a use and discard situation. The installed build takes over the default open action, which is smoother for daily work. Both support LaTeX inverse search and text to speech.

Will it run on Windows XP? Yes, but stay on an old version. The project recommends old builds like 3.1.2 for very old systems, because newer versions no longer cater to that environment. If the machine only reads the occasional PDF, 3.1.2 is plenty.