PDF Tools

Flatten PDF

Bakes the interactive form fields of a PDF (text boxes, checkboxes, dropdowns and similar AcroForm fields) into ordinary page content, so they can no longer be edited. It processes one PDF at a time.

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Flatten a PDF form:

Converts interactive form fields to static text
Filled-in form values stay visible on the page but can no longer be edited
Only form fields are flattened; comments and other annotations are not changed

How to Use

1Fill in your PDF form first in a PDF viewer and save it, if you haven't already.
2Drop the PDF onto the upload area.
3Click Flatten PDF.
4Download flattened.pdf.

About this tool

Updated September 19, 2026

What flattening does to a form

Every interactive form field is turned into ordinary page content. The values stay visible, but the boxes stop being editable.

Before flattening, a filled form stores your answers as properties of live field objects that a reader draws on top of the page. After flattening, those answers are painted into the page itself and the fields are gone. Anyone opening the file sees the completed document and cannot click into a box, tab between fields or change an entry. Checkboxes, radio buttons and dropdown selections are all fixed at whatever they were set to.

Why you would want that

It stops a completed form being altered accidentally, and it makes the file render the same way everywhere.

The second reason matters more than people expect. Form field appearance is generated by the reader, so the same filled PDF can look different in a browser, a phone viewer and a desktop program, and fields occasionally print blank even though they look filled on screen. Flattening removes that whole class of problem by baking the values into the page. It is worth doing on any form you are about to submit, print in bulk, or attach to an application.

It is permanent, so keep the original

There is no way to turn flattened content back into fields, so save the filled version before you flatten it.

Once the values are page content, correcting a typo means editing the page rather than clicking the box, which is far more work. The sensible habit is to keep the editable filled copy for yourself and send the flattened one out. If you flatten first and then find a mistake, you will usually have to fill the blank form again from the start.

What flattening is not

It is not compression, and it is not a way to lock or secure a document.

The file size after flattening is usually similar, and can even rise slightly; use Compress PDF if size is the goal. It also offers no protection. Flattened content is still ordinary text and graphics that editing software can change, so it discourages casual alteration rather than preventing deliberate alteration. If you need a signed record rather than a tidy one, sign the flattened file.

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Features

Flattens AcroForm fields using pdf-lib's form flatten routine
The values currently in the fields stay visible as static content
Accepts one PDF at a time
No settings; a single button does the whole job
Runs in your browser; the file is not uploaded

FAQ

Does flattening make my PDF secure or password protected?

No. It only stops the form fields from being edited. The PDF is not encrypted, and the text can still be copied or edited with other software. This site has no PDF password tool.

What does it do with comments, highlights or stamps?

The code flattens form fields only. Annotations such as comments and highlights are not specifically merged into the page, even though the on-page notes suggest so. Don't rely on this tool to remove or bake in annotations.

Will the file get smaller?

Not reliably. Flattening rewrites the PDF, and the size can go up or down slightly. It is not a compression tool; use Compress PDF if size is the goal.

What if my PDF has no form fields?

Then there is nothing to flatten and you get back a re-saved copy that looks the same. A PDF whose form uses XFA, an older dynamic format, or is damaged may fail to process.

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