Flatten PDF
Make filled forms, comments and layers permanent so the PDF cannot be edited.
Drop PDFs to flatten
or select to choose from your device
Files are processed on this device. Nothing is uploaded.
How to use Flatten PDF
- Add one or more PDFs.
- Choose Form fields to lock a filled form while keeping its text selectable, or Everything, as pictures to make every page a fixed image.
- Select Flatten PDF and download.
How it works
"Flattening" merges interactive parts of a PDF into the page so they can no longer be changed. Form fields: each field’s current value is drawn onto the page and the field itself is removed. The answers look the same but cannot be edited, the text remains real text, and the file stays small. This is what recipients usually want when they ask for a flattened form.
Everything, as pictures: every page is drawn at the resolution you choose and saved as an image. This fixes everything that is visible, including comments, highlights, stamps, layers and signature images, and removes anything that is not visible. The cost is that text can no longer be selected or searched, and the file is usually larger.
The PDF is opened, changed and saved by your own browser. It is not uploaded, so contracts, IDs, bank and medical documents stay on your device.
Example
After filling in a visa form, flatten the form fields before uploading it: the portal sees a normal PDF and nobody can alter your answers.
Frequently asked questions
What does flatten PDF mean?
It makes interactive or layered content a permanent part of the page: form answers, annotations and layers stop being separate, editable objects.
Why do I need to flatten a PDF?
To stop a filled form from being changed, to make sure it prints and displays the same everywhere, or because an upload portal rejects PDFs with active form fields.
Which option should I choose?
"Form fields" for filled forms: it keeps text selectable and the file small. "Everything, as pictures" when comments, highlights or layers must also be fixed, or when a system still rejects the file.
Does flattening reduce file size?
Flattening form fields changes the size very little. Flattening to pictures usually makes the file larger; lower the DPI or use Compress PDF.
Can a flattened PDF be unflattened?
No. Keep a copy of the original if you may need to edit it again.
Limitations
- "Form fields" does not flatten comments and highlights; use "Everything, as pictures" for those.
- Flattening to pictures makes text unselectable and usually enlarges the file.
- Flattening cannot be undone.
- Password-protected PDFs must be unlocked first with Unlock PDF.
Last reviewed November 9, 2026. How we build and test tools.