Check PDF for Hidden Data
Check PDF for hidden data free, in your browser.
Check PDF for hidden data before you send it: choose the file and see what it carries that the screen doesn't show, sorted by what it could give away about you, then remove what you don't want on the same page.
- Free, no sign-up
- Files never leave your device
- Up to 100 MB per file
Drop a PDF file here
or
Up to 100 MB per file. Your files stay on your device.
Your file is checked on your device. It isn't uploaded anywhere.
What next
- Open the new file and check its pages are as you want them before you send it.
- Keep the original yourself: what you removed doesn't come back into the new copy.
Step-by-step guide: Are Deleted PDF Pages Really Gone? Checking What a PDF Still Hides
Finding hidden data in a PDF, and removing it
- 1
Click “Choose a PDF file” or drag your PDF into the box.
- 2
Wait a moment for the check. The results come in three groups: what can carry your words or pictures, what can run actions when the file is opened, and technical leftovers.
- 3
Read each result and leave the remove mark on what you want gone. Anything that can't be removed here has the tool that removes it next to it.
- 4
Press “Remove selected” and download the new file. We check it again and show you what is left in it.
What we look for, and how the results are sorted
We read the whole file, not just what a reader displays: every piece stored in it, what points to what, and what nothing points to any more. Then we sort what we found into three groups. The first is what can carry your words or pictures: older versions of the file, its details and their old copies, XMP blocks, attached files, pages that no longer show, content nothing uses any more, form answers, hidden fields and the XFA copy, notes, bookmarks, text outside a crop frame, and an invisible text layer.
The second is what can run actions when the file is opened: scripts (JavaScript) in the file or its links, and the action that runs on opening. The third is technical leftovers that carry no content, such as a font or a setting nothing uses any more. Each result gives a count, the pages, and short samples to recognise it by, such as a title, a field name or the first words of a note.
We test the check with the same files we use to test our removal tools: a unique phrase is hidden in each of these kinds, the check must find it, and removing it must take it out of the whole saved file, compressed parts included. Why that matters is in our guide Are deleted PDF pages really gone?
What a result means, and what it doesn't say
We never call a file safe. We say what we looked for and what we found. If we found nothing, the file holds none of the kinds listed, which isn't the same as holding nothing about you.
Some things are outside this check altogether. Text inside pictures and scanned pages is part of the picture, so it can't be read as text. And what is visible on a page, like a name in a letterhead or a number in a table, is there for anyone who opens the file, so it isn't hidden. To take part of a page out, use Redact PDF.
When you remove things, we write the file afresh: older versions and everything nothing points to any more leave it. Then we check the new file again and show you what is left, so you see the result yourself rather than taking our word for it.
Example: a price quote edited twice
For this example we made a two-page quote from a made-up removals company, edited twice in a PDF editor: once to change the price, and once to add an internal note for the manager. Then it was sent as it was.
Opened here, the first group shows three results: two older versions saved inside the file, one of them with text that differs from the current version, which is the old price; the author's name in the file details; and one note on page 2, with its first words shown in the result.
Leave all three marked and press “Remove selected”. The file is written afresh without the two older versions, its details are cleared and the note is gone, and the second check comes back with none of these kinds.
When you would use it
Before sending a quote or a contract you edited more than once, to make sure the old price or a deleted clause isn't still inside.
Before publishing a file on a website or sharing it in a group, to see the author name and program stored in it.
After receiving a file from someone you don't know, to see whether it has scripts that run when it opens, or attached files.
Before handing in a filled-in form, to see whether it has hidden fields or notes you forgot to delete.
What to expect
We never call a file safe: we say what we looked for and what we found, and every result lists it.
We don't read text inside pictures and scanned pages, so what is in them doesn't show up in the check.
What is visible on a page isn't hidden, so it isn't listed here. To take part of a page out, use Redact PDF.
Visible form answers and text outside a crop frame can't be removed on this page; each has the right tool named next to it.
A password-protected file can't be checked until you remove the password with Unlock PDF.
Bookmarks or notes you remove don't come back into the new copy, so keep the original if you might need them.
In a digitally signed file, the older saved versions are part of the signature, so they are not ticked for removal, and saving here makes the signature invalid in the new copy. See Visual signature vs digital signature.
Frequently asked questions
Is the hidden data check free?
Yes. No sign-up, no daily limit, and no watermark on your file.
Is my file uploaded for the check?
No. The file is read and checked in your browser, on your device, and isn't sent to us or anyone else. That matters here more than anywhere: a file you want to check is usually one you don't want others to see.
What is hidden in my PDF? What counts as hidden data?
Anything the file carries that a PDF reader does not show: the author and the program that made it, older versions an editor saved inside it, attached files, form answers and hidden fields, the text of notes, pages that no longer show, and scripts that run when the file opens.
Does "nothing found" mean the file is safe?
We don't say that. It means none of the kinds we look for are in the file, and the result lists them all. What is visible on the pages themselves, and anything inside pictures and scanned pages, is outside this check, so look over those yourself.
What are older versions saved inside a file?
Many editors save a change by adding it to the end of the file, so the whole earlier version stays inside, including text you deleted or changed. We count those versions and tell you whether one of them holds text or pages that differ from the current one. Saving here writes the file afresh, so none of them are left.
Why aren't visible form answers removed here?
Because they are usually what you mean to send. We list them so you know whoever gets the file can change or copy them; to fix them into the page, use Flatten PDF. Hidden fields, which nobody reading the form can see, can be removed here.
Should I remove the bookmarks?
Usually not: they are the file's table of contents and make it easier to move around. We list them because their titles are words that can give away what a document held, such as the title of a chapter whose pages you deleted. They stay unless you choose to remove them.
You found an invisible text layer in my scan. Is that a problem?
Usually not. Scanning apps that recognise text lay the page's words over the picture invisibly, so the page can be searched and copied. But that layer holds the page's words as text, so if you covered something in the picture, make sure the text layer doesn't still carry it. To see what is in it, use Copy text from PDF.
Does it work on a phone?
Yes, in a phone's browser as well as on a computer. Very large files can need more memory than some phones have, and we tell you if that happens.