Flatten PDF
Flatten filled PDF form fields into fixed page content in your browser, so the answers can no longer be edited as a form. Comments are not flattened.
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About This Tool
Flatten PDF turns the fields of a fillable form into ordinary page content. Add a completed form, leave Flatten Form Fields ticked and click Flatten PDF. Typed answers, ticks and selections are drawn onto the page and the interactive fields are removed, so nobody can change the answers by clicking into the form.
Flattening is carried out by the open-source pdf-lib library. It draws the stored appearance of each field; fields that have no stored appearance are drawn fresh in a standard font, so a value can look a little different from how your reader showed it. The confirmation reports how many form fields were flattened. If it mentions none, nothing was flattened: either the file had no fields, or they could not be processed and the copy was simply saved again.
Despite the extra boxes on the page, the current version flattens form fields only. The annotations and layers options are not acted on, so comments, highlights, stamps and optional content layers come out as they went in. To fix markup into the page, Rasterize PDF redraws each page as an image; to delete it, use Remove Annotations. One file is handled at a time, and a password-protected file should be unlocked with Decrypt PDF first.
Everything runs in your browser tab and the form is not uploaded. A flattened copy is harder to alter by accident, but page content can still be edited with PDF software, so it does not prove that a completed checklist or training record is unchanged. Keep the original where your records procedures require.
How to Use
Add the filled form
Complete the form first, for example in Form Filler, then drop the PDF on the upload area.
Check the options
Leave Flatten Form Fields ticked. The other options do not change the output in this version.
Flatten and download
Click Flatten PDF, read the confirmation, then download the copy named with _flattened.
Check the result
Open the copy and confirm that the answers appear on the page and the fields can no longer be clicked.
Use Cases
Sending a completed application
Fix the answers on an application or enrolment form so the recipient sees exactly what you entered.
Filing completed forms
Keep finished checklists or training forms as static pages rather than editable fields.
Consistent printing
Make filled values appear the same in every viewer and printer, without relying on form support in the reader.
Frequently Asked Questions
Does Flatten PDF flatten comments and annotations?
No. Only form fields are flattened at present, even though an annotations option appears. Rasterize PDF can fix markup into page images, and Remove Annotations deletes it.
Can a flattened form be edited again?
Not as a form, because the fields are gone. The drawn values are ordinary page content, which PDF editing software can still change.
Why does my filled text look different?
Fields without a stored appearance are redrawn in a standard font before flattening, so the result can differ from how your reader displayed them. Check the copy before sending it.
Nothing seems to have changed. Why?
If the confirmation does not mention form fields, the PDF had none, or they could not be processed. A form that is only a scan or a flat image has no fields to flatten.
Can I undo flattening?
No. Keep the original fillable PDF if you might need to change the answers later.