About the Flatten PDF
Flatten PDF makes what you see on the page permanent. In Form fields mode, the text you typed and the boxes you ticked are drawn into the page and the fillable fields are removed, while the rest of the text stays selectable. In Everything mode, every page is drawn as a picture and rebuilt into a new PDF, so nothing can be edited, selected or searched afterwards. Choose the mode that fits, click Flatten PDF and download the result. Your file is processed on your device and is never uploaded.
Updated September 2026
How to use the Flatten PDF
- 1Select the PDF you want to flatten.
- 2Choose Form fields to keep text selectable, or Everything to turn pages into pictures.
- 3In picture mode, pick a resolution in dpi. Higher is sharper but makes a bigger file.
- 4Click Flatten PDF and wait for the progress line to finish.
- 5Click Download PDF.
What flattening does
A PDF can hold several layers: the fixed page, form fields you can type into, and annotations such as stamps or notes. Some viewers show these layers differently, and anyone with the right software can change a field. Flattening turns those layers into ordinary page content.
The visible result is the same, but the file becomes a plain page. That is why flattening is popular before you email a completed application, print a form, or archive a signed document.
Form fields or the whole page
Form fields mode is gentle. It writes each field's value into the page and removes the field, and the remaining text stays sharp and selectable. Use it for application forms, tax forms and worksheets. Comments, highlights and some signature appearances may remain as separate annotations in certain files, so check the result in a viewer.
Everything mode is stronger. It draws each page as a picture, then builds a new PDF from those pictures. Use it when a file shows differently in different viewers, or when you want every layer locked in. The cost is that text is no longer text, and any digital signature is lost.
Sending a filled form safely
Fill the form, flatten a copy, then open the flattened copy once to confirm the answers are visible before sending. If a value is missing, go back to the original, fix it and flatten again.
For confidential files, follow with Protect PDF to add a password, or use Redact PDF to blank out details. Flattening does not remove hidden text, so it is not a privacy tool on its own.
File size after flattening
In picture mode the file size depends on how many pages you have and the dpi you pick. A page at 150 dpi is readable on screen and in print for most documents; 300 dpi suits small print or detailed drawings but produces much larger files. If the result is too big, run it through Compress PDF or lower the dpi.
The tool flattens up to 100 pages at a time in picture mode. For longer documents, split them with Split PDF, flatten each part, then join them again with Merge PDF.
Features
- Two modes: form fields only, or every page as a picture
- Keeps text selectable in form fields mode
- Picture quality of 100, 150, 200 or 300 dpi
- Shows how many form fields the file has
- Progress shown page by page
- Private: the PDF never leaves your device
Frequently asked questions
What does it mean to flatten a PDF?
Flattening merges interactive layers, like form fields, into the fixed page so they can no longer be changed. What was a clickable box becomes ordinary text or a mark on the page, and it looks the same to everyone who opens the file.
Will the text still be selectable?
In Form fields mode, yes: the original page text stays as text. In Everything mode, no: each page becomes a picture, so text cannot be selected, copied or searched, although it still prints and displays normally.
Does flattening stop people copying my text?
Only picture mode does that, and only in the sense that copying no longer works. Anyone can still read the picture or run text recognition on it. If you need a password, use Protect PDF instead.
How do I flatten a filled form?
Fill in the form in any PDF reader and save it, then open the file here, leave Form fields selected and click Flatten PDF. The answers become part of the page and the fields disappear, so the recipient cannot alter them.
Does flattening make the file bigger?
Form fields mode usually changes the size very little. Picture mode often makes files larger, especially at 200 or 300 dpi, because each page is stored as a photo. Try 100 or 150 dpi first, then compare.
Can I undo flattening?
No. Keep your original file. A flattened form cannot be edited again, and picture pages cannot be turned back into text without running recognition. Save the flattened copy under a new name, which this tool does for you.