Flatten PDF
Bake form fields and most annotations into the page so they can't change.
Flatten PDF bakes form fields, comments and stamps into the page so they print and display the same everywhere and can no longer be edited. The output is a normal PDF with static content.
Flatten PDF bakes interactive form fields and markup annotations — sticky notes, stamps, ink drawings, highlights, and similar — into fixed page content so they can no longer be changed. The default keeps your text selectable — the page is not re-rendered. A separate rasterize mode flattens everything to images, which does remove the text layer and makes the file much larger. Flatten PDF is one of UnboundPDF's 53 free browser-based PDF and image tools: it runs on your own device with no upload, no account and no watermark, and reports what it measured on the output.
How to flatten PDF — steps & common uses
Updated 19 August 2026
What people use Flatten PDF for
Anyone finalising a filled-in PDF form or annotated document so its field values and markup become permanent and cannot be edited or re-filled.
- Lock a completed form
- Bake form values and annotations into the page
- Make form answers permanent
- Prevent further edits to fields
- Finalise a filled-in form or annotated PDF before sending
How to flatten PDF
- Add your PDF; flattening happens on your device with no upload.
- Choose Flatten form fields & annotations to freeze field values and markup while keeping text selectable, or Rasterize everything to turn pages into images.
- Click Flatten PDF to apply your choice.
- Preview and download the flattened document.
Questions about Flatten PDF 6
Are my files uploaded to a server?
No. UnboundPDF processes PDFs locally in the browser — documents are not uploaded to a server. We have no backend that receives, stores, or scans your files.
What does flattening a form do?
It converts filled-in form fields into permanent page content, so the values display everywhere but can no longer be edited. Text stays selectable in this mode.
What if my PDF has no form fields?
If it has annotations — sticky notes, stamps, ink drawings, highlights, and similar markup — those are flattened instead, so you still get a finished file. Only a PDF with neither form fields nor annotations has nothing to flatten, and the tool says so; you can still choose Rasterize everything to freeze all content as images.
What does flattening actually do?
It merges interactive form fields and most annotations — sticky notes, stamps, ink drawings, and highlights among them — into the page as fixed content, so they display everywhere and can no longer be moved or edited. Popup notes are removed rather than flattened, since they are never printed; an annotation hidden from view is removed without being drawn; and an annotation with no appearance stream to bake is removed and named in the result rather than silently dropped.
Can I still read the text after flattening a form?
Yes. Flattening a form keeps the text as text; it just fixes the field values in place.
Is flattening reversible?
No. Once form fields and annotations are merged into the page, they cannot become editable or interactive again. Keep your original if you may need to edit it later.
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How your files are handled
The work runs on your own device, inside the browser tab — so there is no server to send your document to.
- Nothing is uploaded. We have no backend that receives or stores documents, so we cannot see your files during processing or after.
- Your device does the work. Large documents are handled in stages, pages are rendered as you reach them, and each job is checked against your device before it starts — so a long run takes longer on a phone than on a laptop, nothing is queued behind other people's jobs, and you can stop a run at any point without touching your original file.
- No account and no watermark. The output is a clean file you can use anywhere, with no sign-up and no hourly cap.
More optimize tools
Other free PDF utilities that work the same way — in your browser, no sign-up.