pdfpix

Flatten a PDF

or drop one here
Choose a PDF first.

Make PDF form fields and visible annotations permanent without uploading the file. The tool counts fields, marks, links, signatures and optional-content layers first, so you choose what becomes permanent before anything changes. Links stay clickable, marks without a usable appearance are reported rather than dropped, and page count, page geometry and original selectable text are checked before download.

How to flatten a PDF

  1. Choose a PDF

    Choose a PDF or drop it onto the page. The file stays in this browser tab.

  2. Review what was found

    The tool counts form fields, visible annotation marks, links, signatures and optional-content layers before it changes anything.

  3. Choose what becomes permanent

    Keep form fields and their current values, visible annotation marks or both selected. Links stay clickable. Marks without a usable appearance stay unchanged.

  4. Download the checked file

    The output is reopened. Its page count, page geometry, original selectable text and remaining interactive elements must match the requested result.

What stays unchanged

Links stay interactive. Annotation objects without a usable normal appearance stay in the PDF because removing them could erase visible information. Optional-content layers are reported but not flattened.

Flattening changes the document bytes, so it invalidates existing digital signatures. It does not remove passwords; unlock a protected PDF first.

Before you flatten

Flattening goes one way. Once a field is permanent, nobody can change the answer inside it, including you, so keep the original file. Fill out a PDF form covers completing the fields first, and How to edit a PDF covers what a browser tool can still change once the flatten has run.

How the flattened file is verified

Before anything changes, the tool reads the text and size of every original page. After saving, it reopens the output and requires the same page count, the same page sizes, each page's original text still on that page, and at least 98% of the original non-space characters. With annotations selected, the count of visible annotations must fall by exactly the number made permanent. If any part fails, no download is offered.

Annotations marked hidden, invisible or not for screen display stay in the file as they are. The tool counts them first and says how many will stay unchanged. A comment, highlight or stamp that is made permanent is drawn from its own saved appearance and scaled to the rectangle it covered, so it does not move. An option is unavailable when the PDF has nothing of that kind to make permanent.

Questions about flattening PDFs

What does flattening a PDF do?
It draws form field appearances and visible annotation marks into the page content, then removes the interactive objects it made permanent.
Does text stay selectable?
Yes. The existing page content is not rendered into a picture. The output must retain at least 98% of the original non-space selectable characters.
Do links still work?
Yes. Link annotations are kept rather than flattened.
What happens to comments without a visible appearance?
They stay unchanged. The result names how many could not be made permanent safely.
Does this flatten PDF layers?
No. Optional-content layers are detected and reported, but this version does not merge their visibility states into page content.
What happens to digital signatures?
Changing a signed PDF invalidates its existing signatures. The tool requires explicit confirmation before it flattens a signed file.
Does the PDF leave my browser?
No. Inspection, rewriting and verification all run in this browser tab.
Does flattening only affect filled fields?
No. With form fields selected, every field in the PDF is made permanent, filled or empty. An empty field becomes part of the page and can no longer be typed into. Verification after saving requires that no form field remains.

Related tools

Each runs in a browser tab like this one, reads its own output back before the download, and needs no account. The footer links every tool.

Where to go next