PUB (Microsoft Publisher)
The desktop publishing format that put brochures and newsletters in the hands of anyone with a PC.
| Full name | Microsoft Publisher |
| Extension | .pub |
| MIME type | application/x-mspublisher |
| Developer | Microsoft |
| Released | 1991 |
| Type | Desktop publishing document |
| Container format | Microsoft Compound File Binary (version 2.0 and later) |
| End of life | October 13, 2026 (Microsoft retiring Publisher) |
What is a PUB file?
PUB is the native file format for Microsoft Publisher, a desktop publishing application that Microsoft first released in 1991. Publisher sits between a word processor and professional layout tools, letting users arrange text boxes, images, and shapes on a page with precise control. The format is proprietary and has never had a fully published specification, which makes it difficult to open outside of Microsoft's own software.
A PUB file stores a complete Publisher document, including page layout, text content, images, fonts, color schemes, and design templates. The format uses the Microsoft Compound File Binary structure, a container that organizes data into named streams and storages, similar to a mini file system inside one file. Text, vector shapes, and embedded raster images all live within that container as separate object blocks. Early Publisher 1.0 files used a simpler binary format with the magic header E7AC2C00, but version 2.0 switched to the Compound File structure that has been used ever since.
History
Microsoft launched Publisher in 1991 as a low-cost alternative to professional tools like QuarkXPress and PageMaker, targeting home users and small businesses. Over the following decades the format went through at least 14 internal revisions, with Publisher 2003 through 2013 sharing a directly compatible file layout. In early 2023 Microsoft announced it would retire Publisher on October 13, 2026, after 35 years, directing users toward Word and PowerPoint as replacements.
How it works
PUB files after version 1.0 are Compound File Binary containers divided into named streams. A header section records the file version, document properties, and layout parameters. Object blocks follow the header and each block represents a discrete design element such as a text box, picture frame, or shape, with its position, size, and formatting data stored inline. Image data is embedded directly in the file rather than linked, which keeps everything portable but produces large files when high-resolution photos are used.
What it is used for
- Creating newsletters, brochures, and flyers for print or PDF export
- Designing greeting cards, postcards, and invitations with pixel-accurate layouts
- Producing business cards and letterheads with custom fonts and brand colors
- Archiving or converting older Publisher documents from the 2003-2013 era
How to open it
Microsoft Publisher itself is the only application that reliably opens PUB files without data loss, though Microsoft is retiring it in October 2026. For users without Publisher, online converters and tools like LibreOffice Draw can open many PUB files, though complex layouts with custom fonts or linked text boxes may not convert perfectly.
Pros and cons
Strengths
- Tight integration with Microsoft Office templates and clip art libraries
- Precise page-layout controls that go well beyond a standard word processor
- Single-file format embeds all images, fonts, and content for easy sharing
- Long track record with broad template availability for common print projects
Trade-offs
- Proprietary format with no published specification, making third-party support unreliable
- Microsoft is retiring Publisher in October 2026, leaving the format without active development
- Files can become very large when high-resolution images are embedded
- Virtually no support on macOS or Linux without conversion first
Convert PUB files
Free, in your browser, no signup. Start at the PUB converter, or jump straight to a popular conversion below.
Curious how fast and how small? See our measured conversion benchmarks.
PUB FAQ
Can I open a PUB file without Microsoft Publisher?
You can try, but results vary. LibreOffice Draw includes basic PUB import support, and several online converters can extract the content. Complex layouts with custom fonts, linked text boxes, or Publisher-specific design objects will often shift or lose formatting.
What happens to my PUB files when Microsoft retires Publisher in October 2026?
Your existing files are not deleted and the format does not disappear. You simply lose access to the Publisher application itself if your subscription or license ends. The recommended step is to export important documents to PDF or DOCX before that date.
Why is the PUB file format not supported by more applications?
Microsoft never published a complete specification for the format. Without official documentation, developers must reverse-engineer the binary structure, which is time-consuming and produces incomplete support. This is common with proprietary Office-era formats that were designed to work exclusively within Microsoft's own ecosystem.
What is the best way to convert a PUB file to PDF?
The cleanest method is to open the file in Microsoft Publisher and use File > Export > Create PDF/XPS. If you do not have Publisher, an online converter can produce a usable PDF for simple documents, though complex multi-column layouts or custom fonts may shift during conversion.