Document & PDF
Protect PDF
Password protect a PDF online — fast, easy, and 100% free. Lock any document so only people you choose can open it, encrypted locally in your browser so the password is never transmitted anywhere.
- Encryption happens on-device
- Password never transmitted
- No signup or install
Frequently asked questions
How do I put a password on a PDF?
Upload the PDF, set a password, and download the protected file. Anyone opening it afterward will be required to enter that password.
Is it safe to add a PDF password online?
Yes, because the encryption runs locally in your browser, your file and the password you choose are never sent to any server or third party.
What happens if I try to protect a PDF that's already locked?
You'll be prompted to unlock it with its existing password first, then you can set the new password in the same flow.
Can I set a different password than the one already on the file?
Yes, after unlocking with the original password you choose an entirely new one to re-protect the document.
What if I forget the password I set?
There's no recovery option, since the password isn't stored anywhere — keep a note of it somewhere safe before closing the tab.
Is there a file size limit for protecting a PDF?
No, encryption happens locally in your browser regardless of file size, so there's no server-side upload limit.