How to flatten a PDF
- Drop one or more PDFs into the box above, or click it to choose them.
- Leave Also flatten comments, highlights and stamps ticked, or untick it to flatten only the form fields. Set this before adding the file.
- Wait a moment, then read the result. It says how many fields and comments were flattened and what was checked afterwards.
- Click Download. The file name ends in
-flattened.pdf; your original is not changed.
When flattening helps
- A filled form looks blank to the person you sent it to. See the next section.
- The form is finished. An application or an order form shouldn’t change by accident when someone clicks on it.
- A print shop or an upload portal rejects the file, or prints it with empty boxes. Flattened answers are plain page content, so nothing depends on how a form is handled.
- Comments should stay visible on a marked-up contract or proof, in every app, including ones that hide comments.
Don’t flatten a form someone still has to fill, and flatten before signing rather than after, because flattening changes the file and a digital signature stops verifying.
Why a filled form can look blank elsewhere
A PDF form field keeps an answer in two places: the value itself, and a small drawing of how that value looks. Most apps show the drawing. Some programs and form-filling services save only the value and leave the drawing out, with a note asking the viewer to make its own. Viewers that do so show the answer. Viewers that don’t show an empty box, although the answer is in the file.
This tool looks for those fields, draws the missing answer and puts it on the page. The result says how many fields needed it. The lettering in those fields is the tool’s own, because the original app never drew any, so look them over before sending.
What this tool does differently
| Question | What happens here |
|---|---|
| Does the page become an image? | No. Text stays selectable and searchable, and the file stays about the same size |
| Do hidden copies of the answers stay in the file? | No. The fields, their stored values, any XFA copy of the form and flattened comments are removed from the file, not just unlinked from the page |
| Do links keep working? | Yes. Links are not comments and are left alone |
| What about Print and Submit buttons? | A button set not to print is left out, so it doesn’t end up as a dead picture on the page. Hidden items stay hidden |
| A comment with nothing to draw? | It stays as a comment, and the result counts it, rather than vanishing without a word |
| Is the result checked? | The saved file is reopened with a separate PDF reader. It counts what is left and looks for the typed answers in the page text |
What flattening doesn’t do
- It isn’t redaction. Covered content can stay in the file. To remove text for good, use Redact PDF.
- It isn’t a lock. A PDF editor can still change a flattened page. To restrict a file, use Protect PDF.
- It doesn’t merge layers. Layered files stay layered.
- It can’t read a pure XFA form, the kind that shows “Please wait…”. See why you can’t type in some PDF forms.
- Text inside a sticky note is lost. The note’s icon goes on the page, and the result warns you. Untick the comments option to keep notes as they are.
Related tools
Still have to type the answers? Fill PDF Form fills and can flatten in one go. Need a signature on the finished copy? Sign PDF adds one. If the file is locked, Unlock PDF tells you what kind of lock it has.