How to Flatten a PDF

Q: Is flattening the same as turning a PDF into images?

Only when **Flatten as** is set to Image, which renders each page as a picture at the DPI you choose. The default Vector method merges the interactive layer into the page while text stays text, so the file stays small and searchable.

Flattening fixes whatever floats on top of a PDF page, typed form answers, sticky notes, highlights, stamps and signature boxes, into the page itself, so the file looks the same in every viewer and the answers can no longer be changed.

or drop PDF files here ·

Max 95 MB per file· Up to 20 files· Deleted after 30 minutes

Flatten

What to flatten

Files are processed on our servers and deleted after 30 minutes.

How to use this tool

1
Fill, sign and save
Finish the form and add a drawn or typed signature in your usual PDF app, save, then upload that one file here (up to 95 MB).
2
Pick what to flatten
What to flatten is set to Everything. Choose Form fields, Comments & markup or Signatures if part of the file should stay editable.
3
Flatten and check
Press Flatten, download the result and click into an answer: if no cursor appears and no box highlights, the PDF is flat.

A filled PDF form is two things stacked: the printed page, and a layer of interactive objects floating over it. Flattening merges the two. Here is what that means, three ways to do it, and how to tell which one your situation needs.

What does it mean to flatten a PDF?

Flatten (PDF)burn in · bake in: To draw every form field, annotation and signature widget into the page content and remove the interactive object behind it, so an editable value becomes ordinary text or graphics.

Fillable fields have been part of PDF since version 1.2 in 1996. Each one stores a value plus an appearance, a small drawing of that value which the viewer displays. Trouble starts when a viewer redraws or ignores that appearance: a phone preview, a browser tab or an e-filing portal may show an empty box, a different font or nothing at all. Comments behave the same way; some viewers hide them, some print them, and anyone can delete them.

Signatures are the subtle case. A signature drawn or typed with a fill-and-sign tool is usually a stamp annotation, and flattening turns it into part of the page. A certificate-based digital signature is different: it is a cryptographic seal over the exact bytes of the file, and any change, flattening included, makes viewers report it as invalid. Flatten before such a signature is applied, never after.

How to flatten a PDF on Windows, Mac or in a browser

Windows

01Open the filled PDF in Acrobat Reader or Edge and press Ctrl + P.
02In Acrobat Reader, set Comments & Forms to include markups if notes should stay visible.
03Choose Microsoft Print to PDF as the printer and save the new file.

Mac

01Open the PDF in Preview and choose File, then Print.
02Open the PDF menu at the bottom left of the print dialog.
03Pick Save as PDF; visible fields and notes become page content.

Browser, any device

01Upload the PDF to the flatten tool on this page.
02Leave Flatten as on Vector so text stays selectable.
03Press Flatten; links and bookmarks are kept by default.

When Print to PDF is enough to flatten a PDF form, and when it is not

	Flatten, Vector	Flatten, Image	Print to PDF
Form answers fixed in place	yes	yes	yes
Text stays selectable	yes	no	Usually
Clickable links kept	Optional	Optional	no
Bookmarks kept	Optional	Optional	no
Flatten only comments or only fields	yes	yes	no
Original page size guaranteed	yes	yes	no

Print to PDF works because a virtual printer only receives what is visible, which makes it a fair choice for a one-off form with no links that someone will read once and file. Its catches are quiet ones: the printer's paper setting can rescale an A4 form to Letter or the other way round, links, bookmarks and document properties disappear, and comments only come along when the print dialog is told to include them.

When the recipient is a court, a registry or an archive, use a real flatten and keep the page exactly as it was. If they also want an archival file, convert the flattened copy with PDF to PDF/A. For the tool side, what it keeps, what happens to file size and how your upload is handled, see flatten PDF online.

Flattening a PDF: questions

How can I tell whether a PDF is already flattened?

Click where the answers are. If a text cursor appears in a box, fields turn blue, or the comments panel lists notes, the interactive layer is still live. In a flat file the answers select like any other text on the page and those panels are empty.

Does flattening make a PDF read-only?

It removes the editable layer, not the ability to edit. Anyone with a PDF editor can still change text on a page, flattened or not. To discourage that, add a permissions password with protect PDF after flattening.

Should I flatten before or after signing?

With a drawn or typed signature, sign first and then flatten so the signature becomes part of the page. With a certificate-based digital signature, reverse the order: flatten the form, then sign, because any change after signing invalidates the certificate.

Can I unflatten a PDF and get the form fields back?

No. Once values are drawn into the page, the field objects are gone and there is nothing to restore. Keep the fillable original under a different file name, so you can fix a typo and flatten again.

Why do flattened answers appear in a different font?

Flattening bakes in each field's stored appearance, and that appearance is created by whichever app filled the form. Some phone and browser viewers create it with a substitute font. Fill and save the form in a full PDF app, then flatten again.

Is flattening the same as turning a PDF into images?

Only when Flatten as is set to Image, which renders each page as a picture at the DPI you choose. The default Vector method merges the interactive layer into the page while text stays text, so the file stays small and searchable.