What does flattening a PDF do?

Flattening permanently merges annotations (markups, comments, stamps) and form field values into the page content itself. The result looks identical but the interactive elements are gone -- recipients cannot edit, delete, or accidentally move your markups.

Is PDF Flattener free?

Yes, completely free. No paid plans, no trial limits, no signup required.

Are my PDF files private?

Your files never leave your device. All processing happens locally in your browser -- nothing is uploaded to any server.

What is the difference between flattening and printing to PDF?

Printing to PDF rasterizes the page -- everything becomes pixels, losing text selectability and making the file larger. True flattening keeps the page content as-is and only merges the annotation layer, preserving text quality and keeping file size small.

Do I need Adobe Acrobat to flatten a PDF?

No. PDF Flattener does the same job as Adobe Acrobat's flatten function for free, entirely in your browser, with no install required.

Why do AEC professionals flatten PDFs before sending?

Architects, engineers, and contractors mark up drawing sets with redlines and comments. Before sending to a client or uploading to a project portal, they flatten the PDF so the markups are permanently part of the sheet -- clients cannot accidentally delete or modify the redlines.

Can I flatten a PDF offline?

Yes. After your first visit the tool works offline -- it is a Progressive Web App (PWA) you can install to your device.

Flatten PDF Online, Free

Drop your PDF here or click to select

Enable JavaScript to use the tool

Why flatten a PDF?

When you send a marked-up PDF to a client or upload to a project portal, annotations and form fields stay interactive -- recipients can accidentally delete or edit your redlines. Flattening permanently merges them into the page so the content is locked and can no longer be modified.

Architects, engineers, and contractors flatten drawing sets before handing off to clients. PDF Flattener does the same job as Adobe Acrobat's flatten function -- for free, in your browser, with no install or file upload required.

How to flatten a PDF

Drop your PDF onto the page or click to select it.
Choose what to flatten: annotations, form fields, or both.
Download the flattened PDF. Markups are permanently embedded.

What gets flattened?

Annotations -- highlights, comments, stamps, freehand drawings, redlines
Form fields -- text boxes, checkboxes, dropdowns become static text

Files are processed entirely in your browser. Nothing is uploaded to any server. No account required, no daily limits.