Flatten PDF Form Fields
Flatten a filled PDF by converting its interactive AcroForm fields into static page content. The values remain visible, but the fields are no longer editable or interactive in the downloaded copy. Appearance streams are generated before flattening, so what the recipient sees is what you saw. Flattening is useful before sharing a completed form or sending it into a workflow that should not allow another editor to change field values. It does not repair a damaged PDF, remove annotations unrelated to form fields, create a PDF/A archive, or certify that the displayed appearance is legally sufficient. Keep the editable source until the static copy has been reviewed.
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Add to Chrome — freeWhat it does
- AcroForm field count
- Local form flattening
- Static values in downloaded PDF
- No account, and nothing kept after 30 minutes
- Honest refusal when no fields exist
How to use Flatten PDF
- 1
Choose the filled PDF
Select the PDF containing interactive fields such as text boxes, checkboxes, radio buttons, or dropdowns. The browser reads it locally.
- 2
Flatten the fields
Press Flatten form fields. The tool counts the fields, converts their appearances into static page content, and leaves the original file untouched.
- 3
Review the static copy
Open the result in a PDF reader and check every value, checkbox, signature area, font, and page. The downloaded fields should no longer accept editing.
- 4
Download and preserve the source
Download the flattened copy for sharing, but preserve the editable source until the recipient or workflow confirms the result is complete.
How it works
Delivery checklist
Reopen the result in a second viewer and confirm that fields, page count, and visible annotations are still correct before sending it.
Delivery copy review
Reopen the flattened file, check page count and text selection, and verify that values and visible annotations survived. Never discard the editable source before this review.
When not to flatten
Do not flatten the only copy of a form that still needs field editing, validation, or accessibility review. Flattening can remove widget behavior, annotations, calculations, links, or signature semantics even when pages look correct. Use a named delivery copy, compare it with the source, and reopen it in the recipient's viewer. Check values, page count, and important attachments before archiving the result.
Flattening checklist
Keep the original PDF before flattening and verify the result in the viewer used by the recipient. Check form values, annotations, page count, links, signatures, and embedded attachments because flattening can turn interactive objects into fixed page content or remove features that cannot be represented safely. Use a flattened copy for a stable handoff, not as the only archive when someone may need to edit the form or validate a digital signature later.
The page loads the document with pdf-lib, asks its AcroForm model for interactive fields, and calls the library's flatten operation. That operation uses the current field appearances as page content and removes the interactive field controls. The document is then serialized into a new local PDF Blob. No rasterization is involved, so ordinary page text and vectors are not intentionally converted into screenshots.
Flattening is different from password protection and redaction. A flattened value is still visible and can be copied or covered by another editor. It also does not erase every annotation or metadata object. The tool reports a PDF with no fields as a useful no-op rather than producing a misleadingly changed file.
When to use it
Use flattening before sharing a completed form, uploading a static application, or archiving a filled worksheet where future edits should be discouraged. Keep the editable source in a controlled location, and use signatures, permissions, or secure redaction when the requirement is authenticity or information removal rather than a static appearance.
Examples
Sharing a completed application
Flattening prevents an ordinary PDF viewer from changing the submitted values accidentally. It does not add a digital signature or prove who entered them.
Detecting a non-form PDF
The tool refuses instead of rewriting an unrelated PDF and calling the result a successful flatten. Ordinary annotations and text are separate PDF structures.
Frequently asked questions
Will flattened PDF fields still be editable?
The interactive AcroForm fields are removed from the downloaded copy and their current appearances remain as static page content. A viewer should no longer let someone type into those fields, but a person can still edit or annotate the PDF with a separate document editor. Review the output rather than assuming flattening is a security control.
Does flattening remove signatures or annotations?
The operation targets interactive form fields and is not a general annotation sanitizer or signature verifier. Existing signatures, comments, widgets, and unusual appearances may have application-specific behavior. If a signed document matters, verify the signature and output validity in the workflow that owns it.
Is my PDF uploaded while it is flattened?
No — and how it works changed on 2026-08-26. The file is sent to Prathom's own server, processed there, and deleted the moment the response is sent; nothing is stored and no account is needed. It used to run inside the browser tab, which was slower, capped by the memory that tab had, and — for several of these tools — produced worse output. The resulting Blob is created for your download and is not stored by this tool. Keep in mind that local processing does not override your device's own extensions or administration.
Can flattening repair a corrupt PDF or make PDF/A?
No. It parses the document and only changes form field structures. It does not repair broken cross-reference tables, validate PDF/A conformance, encrypt the result, or guarantee compatibility with every reader. Use a dedicated standards-aware or repair workflow for those requirements.