Flatten PDF: Lock Form Fields Online
To flatten a PDF means to merge its interactive layers, such as fillable form fields and comments, into the page so they can no longer be edited. People flatten PDFs before sending a completed form, so that the answers cannot be changed, or when a viewer shows empty fields. This flatten PDF tool has two modes. Form flatten keeps the text selectable and turns each filled field into plain page content. Image mode renders every page, including annotations, into a flat picture at the quality you choose. Your file stays on your device.
Flatten PDF
Flatten a PDF online: lock filled form fields into the page or turn every page into a flat image. Private, no upload.
How to use the Flatten PDF
- Choose or drop the PDF.
- Pick a mode: Flatten form fields (keeps text) or Flatten everything to images.
- For image mode choose the resolution.
- Press Flatten PDF and download the file.
Features
- Flatten form fields and keep text selectable
- Flatten everything, including comments and stamps, to images
- Choose 100, 150 or 200 dpi in image mode
- Tells you how many fields were flattened
- Works in your browser, nothing is uploaded
- Keeps the original page sizes
Frequently asked questions
What does it mean to flatten a PDF?
It combines the interactive parts, such as form fields, into the static page. The values are still visible but you can no longer click into a field and change them.
Which mode should I choose?
Use Flatten form fields for a filled form. The text stays selectable and the file stays small. Use Flatten everything to images when you also need to remove comments, highlights or other annotations, or to make sure nothing can be selected.
Can I undo flattening?
No. A flattened file cannot be turned back into a fillable form, so keep your original copy.
Why is the image mode file larger and not searchable?
Each page becomes a picture, so the text is no longer real text and the file is larger. Choose a lower resolution to reduce the size, or use the form mode if you need search.
Is my PDF uploaded?
No. The PDF is processed in your browser. Only the PDF libraries are downloaded the first time you use the tool.