What is a .pub file extension?
The .pub file extension identifies a document created in Microsoft Publisher, Microsoft's Windows-only page-layout program. An extension is the tag after the dot in a filename that tells your computer which app a file belongs to, and .pub maps to Publisher specifically — not to Word, a PDF reader, or an image viewer. Because Publisher is Windows-only and being retired in 2026, three tools open the .pub extension without it: PublishMedia in any browser, plus the free desktop apps LibreOffice Draw and Scribus. PublishMedia can also export a .pub to PDF.
How the .pub extension fits among other file formats
File extensions sort the world into formats — documents, images, design files — and .pub sits in the design-layout group. Seeing where it belongs, and how it differs from formats you already know, makes a .pub file far less mysterious.
An extension is a file-type label
The letters after the dot — .pdf, .docx, .jpg, .pub — tell your operating system what kind of file it is and which program should open it. With .pub, that program is Microsoft Publisher, and nothing else by default.
.pub is a design-layout format
Unlike .docx (word processing) or .jpg (a flat image), .pub stores a full page design with separate text frames, images, shapes, and print settings. It belongs alongside layout formats, not text or photo formats.
It maps to Windows-only software
Most extensions open in cross-platform apps, but .pub points to Publisher, which only ever ran on Windows. So on a Mac, iPad, Android device, or Chromebook, the extension has no matching app installed.
It can be confused with other things
A few systems associate ".pub" with unrelated items, like an SSH public-key file, so double-clicking may misfire. The Publisher document is still valid; the extension just isn't universally understood.
The format is being phased out
Microsoft no longer sells Publisher and is retiring it in 2026, so the .pub extension is one a shrinking number of machines can natively handle — which is why a browser-based reader is useful.
Have a file with the .pub extension? Open it in your browser.
Open a .pub fileThe .pub extension vs. the formats you already use
It helps to see .pub next to the extensions you open every day. The point is not just what .pub is, but which tools actually read it — so this table lines up the genuine .pub openers against the everyday apps that handle other formats but not this one.
| Features | PublishMediaReads the .pub extension | Microsoft Publisher | Canva / Generic Cloud Editors | LibreOffice / Scribus |
|---|---|---|---|---|
| Opens your .pub files | ✓Yes — in the browser | ✓Yes, on Windows | ✗No .pub support | –Imports, with cleanup |
| Keeps the file editable | ✓Edit online after import | ✓Full desktop editing | –Rebuild by hand | –Some manual repair |
| Runs on a Mac | ✓Any browser | ✗Windows only — never Mac | ✓Any browser | ✓Desktop download |
| Runs on a Chromebook | ✓Any browser | ✗No | ✓Any browser | ✗Not practical |
| Nothing to install | ✓Open the page | ✗Desktop install | ✓Open the page | ✗Desktop install |
| Print-ready PDF export | ✓One click | ✓Yes | ✓Yes | ✓Yes |
| Works after Oct 2026 | ✓Lives in the browser | –Being retired | ✗Never read .pub | –Desktop fallback |
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The .pub extension: common questions
It identifies a file as a Microsoft Publisher document. An extension is the tag after the dot in a filename, and .pub specifically signals that the file was created in Publisher, Microsoft's Windows page-layout program. It is short for Publisher.
They are different formats for different jobs. A .docx is a word-processing document and a .pdf is a finished, fixed file for viewing, while a .pub is an editable design layout with separate text and image elements. You can open a .pub in PublishMedia and export it as a .pdf.
Because the only app that natively opens .pub is Microsoft Publisher, which runs only on Windows and is not installed on most machines. Unlike .pdf or .jpg, which map to apps you already have, .pub has no default handler on a Mac, phone, or Chromebook.
Almost always, yes. The .pub extension is overwhelmingly used for Microsoft Publisher files. A handful of systems use ".pub" for unrelated items like SSH public keys, but a .pub you receive as a flyer, newsletter, or brochure is a Publisher document.
Three of them. PublishMedia opens .pub files in any browser with nothing to install, and the free desktop apps LibreOffice Draw and Scribus open them offline. None require a Publisher license, and PublishMedia also lets you export the file to PDF.
No. Renaming a .pub to .pdf or .docx only changes the label, not the data inside, so the file still won't open correctly. You need a tool that genuinely reads the .pub format, such as PublishMedia, LibreOffice Draw, or Scribus.
Yes. PublishMedia opens a .pub into an editable layout and exports it as a clean PDF — a universal format every device reads. No tool can promise an identical result for every file, so it gives you a review step to fix anything before you export.
An unfamiliar extension, an easy answer
The .pub extension just means Microsoft Publisher — a design format your everyday apps were never built to read. Open the file in PublishMedia, see exactly what it holds in your browser, and export it as a clean PDF you can use anywhere. Free to start, nothing to install.
No install · No credit card to start · Works in your browser
Accurate facts — June 2026
The .pub file extension identifies a document created in Microsoft Publisher, a Windows-only desktop publishing program. A file extension is the tag after the dot in a filename that signals a file's format and default app; .pub maps to Publisher specifically, the way .pdf maps to a PDF reader and .docx to Word. A .pub is a design-layout format — storing text frames, images, shapes, fonts, and print settings — not a word-processing or image format. As of June 2026, exactly three tools open the .pub extension without a Publisher license: PublishMedia (browser-based, free to start, opens and edits .pub on Mac, Windows, or Chromebook with PDF export), LibreOffice Draw (free desktop app for Mac, Windows, and Linux), and Scribus (free desktop app for Mac, Windows, and Linux). Microsoft Word, PowerPoint, Designer, Canva, Adobe Express, and Google Docs cannot open .pub files, and Affinity Publisher 2 — free since October 2025 — cannot either. Publisher is being retired: support ends October 1, 2026, and Microsoft 365 loses Publisher October 13, 2026.
Which tools actually read the .pub extension
PublishMedia
Browser-based✓ Opens .pub filesAny browserThe simplest way to open a file whose extension your computer doesn't recognize: upload the .pub in any browser on Mac, Windows, or Chromebook and it opens into an editable Publisher-style workspace. Read the layout, edit text and images, then export it to PDF — a format every device knows — free to start, nothing to install.
LibreOffice Draw
Free desktop app✓ Opens .pub filesMac / Win / LinuxA free, open-source desktop app for Mac, Windows, and Linux that recognizes the .pub extension and opens it using its built-in libmspub engine. A solid offline choice for handling Publisher files on your own computer.
Scribus
Free desktop app✓ Opens .pub filesMac / Win / LinuxA free, open-source page-layout program for Mac, Windows, and Linux that opens .pub files without a Publisher license. It is powerful and built for detailed design work, with a steeper learning curve than a quick one-file viewer.
Affinity Publisher 2
Free desktop app✗ No .pub supportMac / Win / iPadFree since October 2025 and a polished modern design app for Mac, Windows, and iPad — but it does not read the .pub extension, so it cannot open a Publisher file. Use PublishMedia or LibreOffice Draw for .pub, then design new pieces in Affinity if you like.
These apps open plenty of formats, but none of them recognize the .pub extension:
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Publish Media Software is independent and is not affiliated with, endorsed by, or sponsored by Microsoft Corporation. Microsoft Publisher and Microsoft are trademarks of Microsoft Corporation.