How to flatten a PDF
- Choose What to flatten. Pick Form fields for a filled-in form, or Flatten everything (image) for a file with comments, stamps or other markup.
- For image mode, choose a Resolution. 150 DPI suits most screens and office printers.
- Select Choose files or drop your PDF on the box.
- Select Download. The new file ends in
-flattened.
If the file is locked, enter its password first.
Why flatten a form
A fillable PDF keeps each answer in a field that anyone can edit. Some readers show fields differently, hide them when printing, or lose the values when the file is converted. Flattening writes the values into the page itself. The form looks the same, prints the same everywhere, and is safe to send as a final copy, for example a signed application, an invoice or a tax form.
Two modes
Form fields is the quick, precise option. Every field, such as text boxes, check boxes, drop-down lists and radio buttons, becomes part of the page. Text on the rest of the page stays real text, so you can still search and copy it, and the file size barely changes.
Flatten everything (image) renders each page the way a viewer would show it, with annotations, highlights, stamps and form values, then saves the picture as the page. Use it when the markup is not form fields, or when you want a copy that cannot be edited at all. The cost is that text is no longer selectable and the file can grow. Lower the resolution to keep it small, or run the result through Compress PDF.
Tips
- Check your answers before you flatten. You cannot edit them afterwards.
- Add a signature with Sign PDF first, then flatten, so the signature cannot be moved.
- Lock the final file with Protect PDF, or mark it as a copy with Watermark PDF.
- Need a black and white copy to print? Try Grayscale PDF.
- Scans that are already pictures do not need flattening.
Flattening runs with pdf-lib and pdf.js on your device. Your document is never uploaded.