Password protect a PDF
Lock a PDF with a password before you send it. Without the password it can't be opened.
Processed on our server, then deleted
Drop a PDF here
Or drag it anywhere on this page. Up to 10 MB.
Sent to our server for this one job, then deleted. Never stored or logged.
Use a long password you don't use anywhere else. We can't recover it for you.
One PDF up to 10 MB that has no password yet. Processed on our server, then deleted. 10 free server jobs a day per person, shared by all server tools. More: the Protect PDF API (paid per call).
How to password protect a PDF
- Choose a PDF up to 10 MB, or drag it onto the page.
- Type a password twice. Untick printing or copying if readers shouldn't do that.
- Press Protect PDF, download the locked copy, and keep the password safe.
What password protection does
A protected PDF is encrypted: its pages are scrambled with a key derived from your password, so a reader shows nothing until the password is typed in. Our server encrypts the file with AES-256 using the open-source qpdf library and sends the locked copy back to you.
Tips
- Send the password separately from the file, for example by text message instead of in the same email.
- Want a visible "Confidential" mark too? Add one with Watermark PDF first; it runs in your browser.
Questions
Are my PDF and password uploaded?
Yes. Unlike most tools on this site, this one runs on our server: your PDF and the password are sent over HTTPS, the file is encrypted, and the locked copy is sent straight back to your browser. The file and the password exist on the server only while the job runs, in memory and in a private temporary folder that is deleted the moment the job ends. We never store or log the file or the password.
How strong is the protection?
The PDF is encrypted with AES-256, the strongest standard PDF encryption, which every current PDF reader supports. The real strength is your password: use a long one that isn't used anywhere else. Our Password generator makes one in your browser.
What if I forget the password?
The file can't be opened, and we can't help: we never keep the password or the file. Keep your unprotected original, or store the password in a password manager.
What do the print and copy options do?
They limit what someone who knows the password may do: print the document, or copy its text. Most PDF readers respect these limits, but they aren't as strong as the password itself. A separate, random owner password nobody knows guards the limits.
Can I protect a PDF that already has a password?
Not directly. Remove the old password first with Unlock PDF, then protect the copy with the new one.
Is there a limit?
Files up to 10 MB, and 10 free server jobs a day per person, shared by all of our server tools. Only jobs that succeed count, and the count resets at midnight UTC.
What is the human check?
Before a job runs, Cloudflare Turnstile checks that a person, not a bot, is using the tool. It is usually invisible; sometimes it asks you to tick a box.