What is the PUB file format?
Files with the .pub extension are document files created and supported by Microsoft Publisher, one of the Microsoft Office suite applications. .pub files are rich-layout documents capable of containing text, raster and vector images, diagrams, charts, and embedded metadata. They are commonly used to produce publications such as brochures, posters, postcards, and leaflets.
.pub files are also used to create templates for websites and email messages. The format is proprietary, based on the OLE2 Compound File Binary container - the same low-level structure shared with legacy .doc and .xls files - and is supported by only a limited number of applications. This can make sharing .pub documents problematic, since a recipient generally needs a compatible program to open and view the content correctly. The following approaches can help:
- Export the finished document to HTML format. This makes the content viewable in any standard web browser; the recipient cannot edit the layout, but the visual result is reliably accessible.
- If the project is largely text-based with few complex layout elements, saving or converting it to a .DOCX file is an option. Text formatting is largely preserved, though detailed page layout and graphic elements may not transfer cleanly.
- Export to PDF to preserve the exact visual layout for distribution without requiring Publisher on the recipient's machine.
- If editing the file is necessary, the recipient must install one of the programs that provide full support for this format - such as Microsoft Publisher itself or LibreOffice Draw, which offers partial
.pubimport.
Security & safety
RISK: MEDIUMLike other legacy OLE Office binaries, .pub can contain VBA macros and is a possible malware carrier, so don't enable macros on an unexpected Publisher file. The bigger practical risk now is data loss: with Publisher being retired after October 2026, files left only in .pub may become hard to open - convert important PUB files to PDF while you still can. When using online converters, avoid uploading confidential documents.
Format details
in a nutshellFULL NAMEMicrosoft Publisher Document
DEVELOPERMicrosoftsince 1991 (Microsoft Publisher 1.0); modern OLE-based .pub since the late 1990s
CATEGORYLayout Files
MIME TYPEapplication/x-mspublisher
TYPEOLE2 Compound File Binary (proprietary binary)
MAGIC BYTES · FILE SIGNATURE
OFFSET
0001020304050607
HEX
D0CF11E0A1B11AE1
ASCII
········
.pub uses the same Compound File Binary container as legacy .doc/.xls/.ppt, so the first 8 bytes do not uniquely identify Publisher. The file is recognised by internal Publisher-specific streams (e.g. a "Quill" / Escher drawing stream and Publisher document streams).
Programs that open PUB files
Windows2 apps
Microsoft Publisher
Paid Native editor (bundled with some Office/365 plans). Open and immediately Save As PDF to future-proof. Support ends October 2026. 
LibreOffice Draw
Open-source Free. Use File > Open to import the PUB; layout fidelity is partial. Best free option for viewing/extracting content. 
macOS1 app
LibreOffice Draw
Open-source Publisher has no Mac version; LibreOffice Draw imports PUB with partial fidelity. 
Linux1 app
LibreOffice Draw
Open-source Open the PUB in Draw to view/edit with partial fidelity; export to PDF/PNG.
Web1 app
Online PUB-to-PDF converters (e.g. CloudConvert, Zamzar)
Freemium Upload the PUB to a reputable online converter to get a PDF - best for view/print when you have no Publisher. Avoid for sensitive documents. Technical details
deep spec| Container format | OLE2 Compound File Binary (CFB) - the same low-level wrapper used by legacy `.doc`, `.xls`, and `.ppt` files |
| MIME type | `application/x-mspublisher` |
| File signature | `D0 CF 11 E0 A1 B1 1A E1` (hex, offset 0) - generic OLE2 CFB magic bytes; Publisher identity confirmed via internal document streams |
| Publisher identification streams | Quill stream (text and layout engine data) and Escher drawing stream (vector graphics records based on the Escher protocol) |
| Encoding | Proprietary binary; not XML-based or human-readable |
| Platform support | Windows only natively; no official macOS or Linux release of Microsoft Publisher; LibreOffice Draw provides partial cross-platform import |
| Page layout model | Multi-page documents with master pages, snap guides, column grids, and linked text frames |
| Image embedding | Raster images (BMP, JPEG, PNG, GIF, TIFF) and vector graphics (WMF, EMF) embedded within compound file streams |
| Color models | RGB for screen output and CMYK for print production |
| Typography features | Kerning, tracking, drop caps, hyphenation, and text wrapping around objects |
| Native export formats | PDF, XPS, HTML, JPEG, PNG, TIFF, and DOCX via Microsoft Publisher's built-in export |
| File structure | Single monolithic binary file; no ZIP-based bundle or folder package (unlike `.idml` or `.pages` formats) |
| Released | 1991 (Microsoft Publisher 1.0); modern OLE-based .pub since the late 1990s |
| Specification | learn.microsoft.com |
PUB conversions
Possible
.PUB .PDFGUIDE
Yes - if you have Microsoft Publisher, open the file and use File > Export to PDF for a perfect-fidelity…
How to convert
.PUB .JPGGUIDE
Yes, PUB can be converted to JPG - the fastest way is to open the file in Microsoft Publisher and use File >…
How to convert
.PUB .PNGGUIDE
Yes -- open the PUB in Microsoft Publisher or LibreOffice Draw and export each page as a PNG image.
How to convert
.PUB .DOCXGUIDE
Yes - open the PUB in Microsoft Publisher and use File > Save As > Word Document.
How to convert
Community Q&A
asked by usersNo questions yet - be the first to ask about PUB files.
Frequently asked questions
How do I open a PUB file without Microsoft Publisher?
There's no perfect free viewer. LibreOffice Draw imports PUB with partial fidelity, or upload it to a reputable online PUB-to-PDF converter to view/print it.
Is Microsoft Publisher being discontinued?
Yes. Microsoft will no longer support Publisher after October 2026; Microsoft 365 subscribers lose the app, and Microsoft advises converting PUB files to PDF or Word beforehand.
How do I convert a PUB file to PDF?
If you have Publisher, open it and Save As / Export to PDF (best fidelity). Without Publisher, use a trusted online converter or LibreOffice Draw.
Can I open a PUB file on a Mac?
Publisher has no Mac version. Use LibreOffice Draw (partial fidelity) or convert the file to PDF on a Windows PC or via an online converter.
Can Word or Google Docs open PUB files?
No. Word and Google Docs do not read the Publisher format. Convert the PUB to PDF or DOCX first (with Publisher) if you need it there.
What should I do with my PUB files before Publisher ends in 2026?
Open each one in Publisher and Save As PDF (to preserve the exact layout) and/or DOCX (if you need editable text). Do this before October 2026 while Publisher still runs.
References
1Microsoft - [MS-PUB] Publisher binary file format noteslearn.microsoft.com
2Microsoft Support - Publisher will no longer be supported after October 2026support.microsoft.com
