Flatten PDF
Lock filled-in form fields so they can't be edited.
Processed on this device. Nothing is uploaded.
How to use Flatten PDF
- 1
Click "Select files" or drag your files onto the box.
- 2
Change the options if you need to.
- 3
Click "Flatten PDF" and download the result.
A fillable PDF keeps its fields editable, so anyone can change your answers after you send it. Flattening turns the fields into regular page content. What you typed stays visible, the boxes are gone.
Updated:
How to flatten a PDF form online without Acrobat
Flattening takes every form field in the file, such as text boxes, checkboxes, radio buttons and dropdowns, and turns its current value into ordinary page content. The answers stay where they were, but there is nothing left to click or type into. There are no settings: add one or more PDFs and each comes back with "_flattened" in its name.
Only form fields are affected. Comments, highlights and sticky notes are a different kind of object and stay as they are. The rest of the page, including text, images and layout, is not redrawn, so the document still looks and searches the same.
You do not need Adobe Acrobat or any installed program. The tool runs in any modern browser on Windows, Mac, Linux or a phone, and the filled-in form, which often holds an address, a tax number or health details, stays on your device the whole time.
Flatten PDF not working? Common problems and fixes
The answers vanished after flattening
Flattening keeps what is saved in the file. If the form was filled in a viewer and then downloaded or printed without saving, the values may never have been stored. Open your filled file again before flattening. If the boxes are empty there, fill them in, use Save, and try again.
The form only works properly in Adobe Reader
Some official forms use an older Adobe format called XFA, which most other viewers cannot display correctly. This tool works with standard form fields. For an XFA form, fill it in Adobe Reader and use Print, then choose a PDF printer, to get a fixed copy.
Someone could still edit the text
A flattened form cannot be changed by typing into fields, but a full PDF editor can still change any text on a page. If you need a copy where nothing can be edited at all, convert the pages with PDF to JPG and turn the images back into a PDF with JPG to PDF. The text will no longer be selectable.
Flatten PDF vs Print to PDF
Printing to PDF also fixes form values on the page, but it creates a new file from scratch. Depending on the program, it can drop links, bookmarks and comments, change the page size, or turn parts of the page into images.
Flattening touches only the form fields and leaves everything else in the file alone. Use it when you want the document to stay as close to the original as possible. Reach for Print to PDF mainly for XFA forms that flattening cannot handle.
Questions
What does flattening a PDF do?
It merges form fields into the page, so the values become plain content instead of editable boxes.
Will my signature stay?
A drawn or image signature stays. Digital certificate signatures are invalidated by any change to the file, including flattening.
Can I unflatten a PDF?
No. Once fields become page content, there is no record of where the boxes were. The only way back is the copy you had before flattening.
How do I flatten a PDF on a Mac or Chromebook?
Open this page in Safari, Chrome or any other current browser, add the file and download the result. Nothing has to be installed.
Does flattening make a PDF smaller?
Usually the size stays about the same. Field definitions are removed, but their visible content stays, so do not expect a big change. Use Compress PDF if size matters.
Are my files uploaded anywhere?
No. The tool runs in your browser and the files never leave your device. Close the tab and nothing is left behind.