How it works
- Add your PDF. Several files can get the same password together.
- Choose a password and type it twice. Decide whether people may print, copy text or edit.
- Press Protect PDF and download the locked copy. Keep the password safe.
Protect a PDF with a password
Put a password on a PDF before you email it or keep it in cloud storage. The file is encrypted on your own device, so neither the file nor the password is ever sent to a server.
Files stay on your device. Free, with no sign-up.
Protect PDF tool
- 1Add a PDF to protect
- 2Adjust
- 3Download
Files
Done
Nothing left your device.
Choosing a good password
Length matters more than tricks. Three or four unrelated words, such as "river lamp ninety tulip", are easier to remember and much harder to guess than a short word with a number at the end.
Send the password in a different message from the file, ideally a different channel: the file by email, the password by phone or chat.
Frequently asked questions
Are my files uploaded anywhere?
No. Everything happens inside your browser, on your own device. Your files are never sent to a server, and you can confirm that in your browser's network tab. Close the tab and they're gone.
How strong is the protection?
The file is encrypted with AES-256, the strongest encryption the PDF format offers and the one banks use. How hard it is to break depends mostly on the password, so use a long one that is not a name or a date.
What if I forget the password?
It cannot be recovered. Nobody, including this site, can open the file without it. Keep the original unprotected file, or store the password in a password manager.
Do the print, copy and edit settings really stop people?
Most PDF programs respect them, so they work as a polite request and they stop casual use. They are not a lock: only the password truly keeps people out. If the content is sensitive, share the password separately and do not rely on the restrictions alone.
Will the protected PDF open everywhere?
Yes in current versions of Adobe Acrobat, Chrome, Edge, Firefox, macOS Preview, and the PDF apps on Android and iPhone. Very old readers (before 2008) cannot open AES-256 files. For widest compatibility, use letters and numbers in the password, since other characters are handled differently by some apps.
Does protecting change how my PDF looks?
No. The pages are not redrawn. Only the file is encrypted, so text stays sharp and fonts, images and links are untouched.
Can I protect a PDF that already has a password?
Not directly. Remove the old password with Unlock PDF first, then protect the copy with the new one.
Is there a file size limit?
Each file can be up to 100 MB, and up to 300 MB in total. Because the work happens on your device, very large files depend on your available memory. A desktop browser handles them best.