Flatten PDF
Flatten PDF converts interactive form fields and annotations into static page content. The filled values stay visible but can no longer be edited or accidentally cleared, which is what most people want before emailing a completed form.
1 Add your file
Enter the open password to use it here. It is checked in your browser and never sent anywhere.
2 Choose your options
How to flatten PDF
Add your filled PDF
We read the file and tell you how many form fields it contains.
Choose how far to go
Flattening the form fields is enough for most people. Flatten everything to images when you need absolutely nothing to remain editable.
Download the locked PDF
The values are now page content. They display everywhere identically and cannot be cleared by accident.
The layer above the page
A PDF page can carry objects that are not part of it: form fields holding the values you typed, annotations such as comments, highlights and signature images, and optional content groups that can be switched on and off. All of them render on top of the page. None of them is in it.
Flattening draws whatever is currently visible permanently into the page content and discards the separate objects. It is the same operation as merging layers in an image editor: afterwards it looks identical and nothing can be moved.
A worked example
A completed application form prints blank at the print shop. The values are stored in form fields rather than in the page, and that printer's software ignores field appearances. Flattening draws them into the page, after which the document prints the same way everywhere — and usually gets smaller, because the field definitions and their validation scripts go with them.
Limitations worth knowing
- Flattening cannot be undone. The separate objects no longer exist, so always flatten a copy and keep the original.
- Form values become uneditable — the form becomes a picture of a completed form.
- Never flatten a document carrying a cryptographic digital signature: rewriting the page invalidates it.
- Form field labels that screen readers announce are lost, so do not flatten a form that must stay accessible as an interactive form.
- Comment threads, replies, author names and timestamps are removed — useful for privacy, unhelpful if you needed the review history.
Further reading
What Flattening a PDF Actually Does, What PDF Redaction Really Means
Related tools
Flatten PDF — frequently asked questions
So that what you filled in stays filled in. An unflattened form can be edited by the recipient, cleared by a mobile PDF viewer, or rendered differently by software that does not understand the field. Flattening turns the values into ordinary page content that behaves the same everywhere.
Not as a form — the fields no longer exist. The text can still be removed by someone determined enough with the right software, so flattening is a convenience measure, not a security one. Use Protect PDF if you need to restrict editing.
It should not. The field appearance streams that were already being displayed become permanent page content. If a field had no appearance stream, the viewer was guessing at how to draw it, and flattening makes that guess permanent.
In Form fields mode they are left as they are. In Everything mode they are rendered into the page, so they display for anyone but can no longer be clicked, replied to or deleted.
Usually slightly, because the field definitions and their JavaScript go away. The Everything mode often makes it larger, because pages become images.