Last updated: October 2026
How to flatten a PDF
Short answer: drop your PDF above, click Flatten, and download the locked copy. Filled form fields, checkboxes, and annotations are baked permanently into the pages — entirely on your device, with no upload.
Why flatten a PDF?
Lock filled forms — after someone fills your form, flatten it so the answers can't be changed. Archive safely — flattened pages look identical everywhere, with no dependency on form rendering. Share confidently — annotations and comments become permanent page content. And because this tool never uploads your file, it's safe for contracts and legal documents.
Frequently asked questions
Is my PDF uploaded anywhere?
No. The entire conversion runs in your browser with JavaScript — your PDF never leaves your device, which makes this safe for sensitive documents.
Will the text still be selectable after flattening?
No — that's the point of flattening. Pages are re-rendered at high resolution so nothing is editable or extractable as form data. Visual quality is preserved.
What does flattening actually do?
Flattening merges form fields, their filled-in values, checkboxes, and annotations directly into the PDF page content. The result looks identical but nothing can be edited or extracted as form data.
Is there a file size or page limit?
No hard limit — but very large PDFs (hundreds of pages) take longer since every page is processed on your device. Your browser's memory is the only constraint.
Does flattening reduce quality?
Pages are rendered at 2x resolution before reassembly, so print quality stays sharp. Text won't be selectable — keep the original if you need that.