We built our own Publisher conversion engine for .pub files.
Microsoft's sunset of Publisher leaves a lot of people asking what will happen to their documents and life's work. For years LibreOffice was the only mainstream software that could open Publisher files at all, and the volunteers who worked the format out for themselves did genuinely impressive work. If you open a .pub in LibreOffice, it's roughly all there.
But "roughly" and "all there" stop feeling good enough when Microsoft is sunsetting Publisher and YOUR files are your life's work: curriculum you've written, an evolving family recipe book that took years and a lot of love, a 20-year archive of bulletins, or the price list you hand to customers.
For a lot of documents, LibreOffice is fine. Text boxes land roughly where they should. The words are all there. For a long time, PubConvert worked the way almost every Publisher converter on the internet works: we handed your .pub file to LibreOffice and passed its output back to you.
So we decided to read the format ourselves and build our own converter from scratch. Our goal is to reproduce Publisher's own output as faithfully as we can.
What we built
There's no manual for the .pub format. Microsoft never published one, and the format changed across Publisher versions. We've tested our parser on real Publisher documents: newsletters, menus, certificates, raffle tickets, booklets, the kind of files people actually made. We put our output side by side with how those documents are supposed to look, page by page, and fixed what didn't match. Then we did it again. And again. And again. And again. And again....
It's an honorable way to build compatible software, and every line of the resulting converter is our own code, written in Rust and built on what we deduced. Getting the text out was the easy part. Getting the look right, the exact fonts, the table borders, the way text wraps around a photo, is the genuinely hard part, and it's where we've spent our time.
Our engine reads your file directly and renders it with its own PDF renderer. No LibreOffice in the middle. It also writes Word documents YOU CAN ACTUALLY EDIT! and IDML files (the format Adobe InDesign and Affinity Publisher open) straight from a .pub file.
Publisher is still the gold standard for its own files, and we're not going to pretend otherwise. Our goal is to come as close to that as we can, and to keep closing the gap. The way to judge it is with your own file: preview the result before you pay.
What you'll notice
If you converted a file with us before and the result looked a bit off, try it again. Some specifics that behave differently now:
- WordArt keeps its shape, including text on a curve or a full circle
- Tables keep their borders, fills, and alignment, including calendars
- Classic clip art renders instead of disappearing
- Gradients and picture effects survive
- Multi-page documents come out in the right page order
- Rotated and flipped shapes land where they belong
And one thing you won't notice, which matters just as much: if our engine hits a file it can't read (they exist, mostly very old or damaged ones), we automatically fall back to the older conversion path. You still get a result either way.
What this means for the countdown
Microsoft 365 loses Publisher on October 1, 2026. Perpetual copies can still open files; support for those ends October 13, 2026. Our whole reason for building this engine was so that the answer to "what happens to my files?" doesn't depend on software that treats Publisher as an afterthought.
Since launch we've written up the individual pieces: converting to IDML for InDesign and Affinity, Word conversion that stays editable, and the hard parts of Publisher files: WordArt, clip art, and calendars. The engine keeps improving, too. The latest round of fixes is in the August update.
For now: try it on one of your files. The preview is free, and your file is deleted the moment you're done.