Flatten PDF
Turn the fields you filled in into part of the page, so the answers stay put and nobody can type over them. Comments and highlights can go the same way, or stay editable if you would rather. Nothing is turned into an image, so the text is still text, and your file never leaves your device.
100% private. Your files are processed entirely in your browser and never uploaded.
Why flatten a PDF with frisqoo
Nothing is uploaded
The file is read, rewritten and saved inside your browser tab. A filled form usually carries somebody's name, address or signature, which is exactly the sort of thing that should not be passing through a stranger's server.
Text stays selectable
No page is rendered to a picture. We compared the rendered pages of two real forms before and after flattening and found no pixel changed, while the text remained selectable and searchable.
It checks before it acts
The panel counts the fields and marks on your file first and shows you the tally. If there is nothing to flatten it says so, rather than handing back an identical copy and calling it done.
Fields and marks in one pass
Form fields, highlights, comments, stamps and ink are all handled together by default. Turn the switch off and only the form fields are flattened, leaving your comments editable.
No caps and no signup
Flatten one form or forty, at any file size your device can hold in memory. There is no daily quota, no page ceiling, no watermark and no account to create.
Works on a phone
The same page works on a phone browser, including the panel that shows the tally and the switch. Signing and returning a form from a phone is common, and so is needing it flattened first.
How to flatten a PDF
- Drop your filled PDF onto the box above, or press the button to pick it from your device.
- Read the tally in the panel. It lists how many form fields your file has, how many comments or highlights sit above the page, and how many pages there are.
- Press Flatten PDF. The copy saves as
your-file-flattened.pdfwith the answers on the page and the fields gone.
Two or more files skip the editor and run as a batch, with a download for each one and a single ZIP at the end.
Why a filled form keeps changing after you send it
A PDF form is not one thing. The page underneath is fixed, but every box you typed in is a separate interactive object floating above it, holding a value that can be cleared or overwritten by anyone who opens the file. That is useful while the form is being filled in and a nuisance the moment it is finished.
It is why a form you emailed can come back with different numbers in it, why a printer sometimes prints the empty boxes instead of your answers, and why some systems that receive forms reject anything still interactive. Flattening settles all three at once by writing the answers into the page and taking the boxes away.
What is kept, and what is not
- The value in every field, drawn exactly where it appeared
- Ticked checkboxes, chosen radio buttons and selected dropdown options
- Real text, still selectable, searchable and readable aloud
- Your page count, page sizes and orientation
- Highlights, comments and stamps as visible marks on the page
- Fields anyone can type in, clear or overwrite
- Comment popups, and the ability to select or drag a mark
- Any way to turn the saved copy back into a form
The last line is the one to read twice. Flattening is a one-way change to the copy you save. The file you started with is untouched on your device, so keep it if the fields might be needed again.
Flatten everything, or only the fields
Most of the time you want the lot: fields, highlights, comments and stamps, all fixed to the page. That is what happens if you change nothing, and it is the path we have measured on real forms.
There is one case for the other setting. If you are sending a form on to someone who still needs to comment on it, flattening the answers while leaving the comment layer alone keeps their markup usable. When a file has both kinds, the switch appears in the panel. Turning it off uses a different engine that refuses some forms, and when it does the panel tells you so and what to do instead, rather than saving a file it did not change.
Flattening is not the same as locking a document
Plenty of sites blur these together. They are not the same and it matters. A flattened PDF can still be opened by anyone and still be edited in a proper PDF editor, because a page's contents are always editable in principle. What flattening removes is the form itself, so there are no boxes left to fill in and no values left to change by accident.
If what you need is a file that cannot be opened without a password, or one that asks readers not to print or copy it, that is Protect PDF. The two work well together: flatten first so the answers are final, then protect the flattened copy.
Can I flatten a PDF on my phone?
Yes. The whole tool runs in the browser you already have, so there is nothing to install and no desktop step in the middle. Pick the file from your downloads, your files app or your cloud drive, and the flattened copy saves back to your device.
A form filled in and signed on a phone is one of the most common reasons to flatten, so the panel, the tally and the switch are all reachable on a narrow screen rather than being desktop-only.
How long it takes
On a deliberately slow two-core test machine, a one-page form of around 85 KB flattened in about 40 milliseconds, and a second form took around 50. Your own device will differ, and a long document with many pages of comments will take longer than a single-page form, so treat those numbers as a floor rather than a promise.
What does not change is where the work happens. There is no upload, so the time you wait is your own processor and nothing else.
Common ways people use Flatten PDF
- Finishing a filled application or claim form before emailing it back
- Making sure a signed form prints with the answers rather than empty boxes
- Preparing a form for a system that rejects interactive PDFs
- Fixing the answers on a form before merging it into a larger pack
- Turning a marked-up review copy into a flat record of what was said
- Stopping a shared template from being edited each time it is passed on
FAQs about Flatten PDF
What does flattening a PDF actually do?
A form field is a control that sits above the page rather than on it. Flattening draws the value you typed into the page itself and then removes the control. The answer stays exactly where it was and stops being something anyone can edit or clear.
Will the answers I typed into the form still be there?
Yes, and that is the whole point. Ticked boxes stay ticked, a chosen dropdown keeps the option you chose, and typed text stays in place. We tested this on real filled forms and compared the rendered page before and after: not one pixel changed.
Can a flattened PDF be turned back into a form?
No. Once the fields are part of the page there is nothing left to turn back on, here or in any other tool. Your original file is left untouched on your device, so keep it if there is any chance you will need the fields again.
Does flattening turn my pages into images?
No. Some tools flatten by rendering every page to a picture, which makes the file bigger and kills the text. This one rewrites the file structure instead, so the text stays selectable, searchable and readable by a screen reader.
Is flattening the same as protecting a PDF?
It is not, and it is worth being clear about. Flattening stops people typing in the fields because the fields are gone. It does not stop anyone opening the file or editing it in a PDF editor. If you need a password, use Protect PDF instead, or as well.
What happens to highlights, comments and stamps?
By default they are flattened too. The mark stays visible in the same place and stops being a separate object that can be selected, dragged or deleted. A sticky note that had a popup keeps the mark on the page, but the popup window it opened is no longer there to open.
Can I flatten the fields but keep the comments editable?
Yes. When a file has both, the panel shows a switch you can turn off, and only the form fields are flattened. That path uses a different engine and it refuses some forms whose fields carry no stored appearance. If it turns your file down, turning the switch back on will work.
Does it work on a scanned form?
A scan is a picture of a page with no fields on it, so there is nothing to flatten. The tool will tell you that rather than handing back a copy and calling it flattened. If you added comments or highlights to the scan, those can be flattened.
Can I flatten more than one file at once?
Yes. Drop several files in and each one is flattened in turn on your device, with its own row showing what was found and its own download. There is also a single ZIP at the end if you would rather take the lot in one go.
Does my file get uploaded anywhere?
No. The whole job runs inside your browser tab. Nothing is sent to a server, there is no queue and there is nothing to delete afterwards, because the file never left your device in the first place.
Why is my flattened file a slightly different size?
Removing the form machinery usually makes the file a little smaller, because the interactive parts and the appearance streams that fed them are no longer stored separately. On the two forms we measured, one dropped by about three kilobytes and one by four hundred bytes.
Are there forms this will not handle?
XFA forms, the kind built with older Adobe LiveCycle tooling, are a different format layered inside the PDF and we have not tested any. Ordinary AcroForm files, which is nearly everything you will meet, are tested. If your file behaves oddly, Repair PDF is worth a try first.