Merge all layers, annotations, and form fields into a single flat PDF. Prevents editing.
Last Updated: August 2026·Written by Ayaz Dilawar
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What is flattening? Flattening merges all PDF layers, annotations, form fields, and transparency into a single, uneditable image-based layer. Great for finalizing contracts, invoices, and legal documents.
Flattening Options
Flattening pages…
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PDF Flattened!
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Flatten PDF
Flatten PDF online for free. Merge all layers, annotations, and form fields into a single flat PDF. Prevents editing and copying. Browser-based, no upload.
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Stays in your browser
Processing runs on your own device. Your files are not uploaded to a server, so private documents stay private.
Merges annotations, form fields and layers into the page itself, so they can no longer be edited or changed. Filled-in form values stay visible. Flattening cannot be undone, so keep an unflattened copy, and do not use it to hide sensitive content; Redact PDF is the tool for that.
Good to know
Flatten right before sharing a filled form or annotated document so the final version can't be accidentally altered.
Keep an unflattened copy for yourself in case you need to make edits later — flattening isn't reversible.
Flatten after all annotations and form fields are finalized, not before, since flattening locks in whatever's there at that point.
Once flattened, form fields and annotations become plain page content and can't be edited or extracted as data again.
Doesn't reduce file size on its own — pair with Compress PDF if size is also a concern.
Not a redaction tool — flattened text is still visible and can still be copied/read, just no longer editable as a field.
Troubleshooting
The text in my flattened PDF isn't selectable anymore: Flattening currently rebuilds every page as a rendered image, so the text layer is replaced entirely rather than just the form fields and annotations. If you need the body text to stay searchable, keep a copy of the original alongside the flattened version.
Toggling "flatten form fields" / "flatten annotations" doesn't seem to change anything: Every page is rendered as an image regardless of these checkboxes in the current version — there isn't yet a way to flatten only forms/annotations while keeping the rest of the page as live text.
The output file is larger than the original: Rendering pages as images (especially with "High quality" checked) can increase file size compared to the original vector/text-based PDF. Run Compress PDF afterward if size matters.
"Failed to flatten PDF": The source PDF may be corrupted or password-protected. Try Unlock PDF or Repair PDF first.
Frequently asked questions
Interactive elements become part of the page, so they can no longer be edited separately.
Yes. Filled form values stay visible after flattening, but they are no longer editable.
No. Flattening is permanent in the new file, so keep the original PDF if you may need future edits.
No. The document's visual appearance is preserved while making interactive content static.