Flattening makes a PDF more predictable: form fields and annotations are painted into the page so every viewer shows the same result. The trade-off is editability — after flattening, the fields can no longer be filled or the markup changed.
Step by step
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1
Upload your PDF
Drag your PDF onto the box or click Choose file. It is sent over an encrypted connection and only used for this task.
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Set the options
Adjust what to flatten and resolution (dpi). Every field has a sensible default, so you can usually run the tool straight away.
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What flattening does
Form fields and annotations are painted into the page, so the document looks the same everywhere but can no longer be filled in or edited.
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Run it and download
Press Flatten and the page shows progress while it works. When it finishes you get a download link — nothing is emailed and nothing is stored longer than it needs to be.
Forms only vs all content
Only form fields keeps the page as text and vector artwork while freezing the answers. That is usually the right choice for a completed form. All content rasterises the pages, which makes the appearance fixed everywhere but turns text into pixels and removes selectability. Use it only when the visual result matters more than searchability.
Resolution matters
When rasterising, 150 DPI is a reasonable screen-and-office default; use 300 DPI for print. Higher resolution increases file size and does not recover detail that was not in the page. For forms-only flattening, resolution is irrelevant because the text stays vector.
Check what was lost
Open the flattened copy and try to click a form field; it should no longer accept input. Check that signatures, stamps and annotations still appear, and that text is selectable if you chose forms-only. Keep the unflattened master for future edits.
Good habits for Flatten
- Compress is the quickest win for an oversized file — try it before resizing images by hand.
- Flatten before sending a form if you want the answers frozen.
- Repair first if a file refuses to open; many other tools then work on it.
Common questions
Is this tool free?
Yes. Every tool on this site is free to use, with no sign-up, no watermark and no daily task limit.
Do I need to install anything?
No. The tools run in your browser and are processed by this server.
What happens to my files?
They are stored under an unguessable id and swept automatically after a couple of hours. Nothing is shared or indexed.
Does it work on a phone?
Yes. The page pickers and editors are built for touch, so dragging, rotating and selecting pages all work without a mouse.
What does Flatten do exactly?
Makes fillable PDFs read-only. Print & scan in one step
Can I unflatten a PDF?
Not reliably. Flattening is a one-way visual freeze. Keep the original if you may need to edit the fields again.
Does flattening remove annotations?
It paints visible annotations into the page. Hidden comments or metadata may still exist; use Remove Annotations if they must be gone.
Does flattening reduce file size?
Not necessarily. Forms-only may shrink slightly; full rasterisation can increase size. Compress afterwards if needed.