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Flatten PDF Forms and Annotations Online

Flatten PDF files online for free: filled form fields, comments, highlights and stamps get drawn into the page, so they look the same but can't be edited anymore. Upload one or several PDFs and download the flattened copies. Nothing to install.

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// how it works

Flatten PDF Online in 4 Simple Steps

  1. 01Pick your PDF, or drag and drop it here.
  2. 02Add more files, or remove the ones you don't need.
  3. 03Click 'Flatten PDF' to flatten your file for good.
  4. 04Download your flattened PDF straight away.

How PDF flattening works and when to use it

Flatten a PDF when a filled form or a reviewed document has to look the same for everyone and shouldn't be edited anymore. The tool turns form fields, comments, highlights and stamps into ordinary page content.

Flatten a PDF Online

What does it mean to flatten a PDF?

A PDF can carry interactive bits on top of its pages: form fields (AcroForms) and annotations like comments, highlights and stamps. Flattening draws whatever those show into the page itself and removes the interactive layer.

This tool does it in two passes. First the pdf-lib library flattens the form: it draws each field's appearance on the page and removes the field, after redrawing text fields, dropdowns and lists from their values when the form marks its appearances as out of date, so a typed answer with a stale or empty appearance stays visible. Then Ghostscript rewrites the file with annotations inserted into the page content stream so they stop being annotations at all.

How to flatten a PDF online

  1. Pick one or more PDFs (up to 25 MB each), or drag them into the upload area.
  2. Use the + button to add files, or Delete All to start over.
  3. Click “Flatten PDF”.
  4. Download the flattened file, or a ZIP if you flattened several.
Flatten PDF screen with a test form uploaded and the Flatten PDF button
There are no settings: upload the PDFs and click Flatten PDF.

A PDF that opens without a password but restricts editing gets unlocked before flattening. One that needs a password to open is refused, so take the password off first with our Unlock PDF tool.

When should you flatten a PDF form?

Flatten a form once it's complete, right before you send, archive or print it. The recipient sees the values you entered, and nobody can change a field by accident.

Fill the form first, by hand with our Fill Out PDF Form tool or from a JSON or CSV record with PDF Auto Fill. Both leave the fields editable, so flattening comes last.

Flattening also locks review markup in place. Highlights, stamps and text boxes stay visible but can't be moved, edited or deleted one by one anymore. The text of a pop-up sticky note isn't part of the page, though, so read or copy those notes before you flatten.

What flattening changes and what it does not

Flattening doesn't encrypt the file. If the flattened PDF should only open with a password, add one afterwards with Protect PDF from our PDF security tools.

The file gets rewritten, so a digital signature on the original won't verify anymore. Our eSign PDF tool draws a visible signature onto the page, and you can add that before or after flattening.

Keep the editable original if you might need to change a field later, because flattened values can't turn back into fields. A visible DRAFT stamp gets flattened into the page too, so if it shouldn't be there, remove it first with Remove Watermark from our PDF editing tools.

Uploaded files and the flattened copies are processed on PDF-File.com's own server and deleted automatically within two hours.

What happened when we tested Flatten PDF

We flattened our small test form form-template.pdf (6.9 KB, 1 page) with no options to choose. The download, form-template_Flattened.pdf, was 3.0 KB and still had 1 page, ready 0.2 seconds after we clicked on our local test server.

Tested in October 2026.

Flatten PDF results screen with a Download button for the flattened form
The results screen after flattening form-template.pdf.

Will the flattened file pass a portal's check

A grant or submission portal that wants a flattened PDF usually rejects any file that still has form fields, annotations or layers. So we built a worst case: a form with six fields, a sticky note, a highlight, a link and two layers, one of them hidden by default.

After flattening, qpdf found no form fields and no annotations, which means the note, highlight and link were all gone. The hidden layer's content was dropped too, leaving only the visible text on the page.

The typed field values and the page text could still be selected, so the page didn't turn into a picture. That's what a portal's "flattened PDF" rule is looking for.

Frequently Asked Questions About Flattening PDFs

Can I edit fields after flattening?

No. The values become part of the page. Keep the original form if you'll need to edit it later.

Does flattening delete the values I typed?

No. Each field's appearance gets drawn onto the page, and text fields, dropdowns and lists are redrawn from their values when the form asks for that, so the values stay visible.

Are comments and highlights flattened too?

Yes. Annotations are drawn into the page content and stop being separate objects. Copy the text of pop-up notes first, since it isn't printed on the page.

Can I flatten several PDFs at once?

Yes. Add several files before you click Flatten PDF, and the results download as one ZIP.

Is flattening the same as password protection?

No. Flattening removes interactivity; it doesn't add any access control.