Password protect a PDF
Choose a PDF and type a new password twice. The file is encrypted on your device, and nothing is uploaded.
At least 8 characters. A few random words make a strong password that is easy to remember.
To be sure it is the one you meant.
We cannot recover your password: it never leaves your device. Keep it somewhere safe, because without it no one can open the file.
Runs qpdf in your browser. Open-source licenses
How to password protect a PDF
Choose your file, or drop it on the box above.
Type a new password, then type it again.
Select Protect PDF and save the locked file.
How the file is locked
The file is encrypted with AES-256, the strongest encryption the PDF standard has. Any PDF reader asks for the password before it shows a page, and without the password the pages cannot be read.
The password both opens the file and changes its security, and nothing else is restricted: whoever has the password can print, copy and edit as before.
Choosing a password
Use at least 8 characters. The page shows how strong your password looks as you type it; a few random words, such as four words picked from a dictionary, are strong and easy to remember.
We cannot recover your password, because it never leaves your device. Keep it somewhere safe.
Your file never leaves your device
The file is encrypted in your browser with qpdf, an open-source PDF library built to run on your device. No file, page, file name or password is sent to us or to anyone else. The tool itself loads only when you start, so the page stays fast.
A file that already has a password
Type its current password when the page asks, and the new password replaces it. If the file's creator restricted printing, copying or changes, the page asks for its owner password, because protecting it again would remove those restrictions.
How large can the file be?
It depends on your device's memory. If the file is too large for your device, the tool says so before it starts, rather than letting the browser close the tab.
Related tools
- Unlock PDF: Take the password off a file you have the password for.
- Sign PDF: Add your drawn or typed signature to a file.
- Compress PDF: Make a file smaller, or at or under a size you type.
- Merge PDF: Join several files into one, in the order you choose.
- Split PDF: Save pages or ranges of a file as new files.