Add a password to a PDF so it cannot be opened without one. The encryption happens on your device.
Use Password Protect PDF (interactive) — JavaScript required for uploads.
Most online tools ask you to upload both the document and the password you intend to protect it with — to a server you cannot inspect. Here the file never leaves the page and the password never travels, so there is no one to trust.
AES-256 is the right default. AES-128 is for older readers. 40-bit exists only for very old software and is not secure — avoid it unless something specifically requires it.
Yes, completely free and with no account.
No. It is used by code running in your browser tab. Nothing is transmitted — check your Network tab while you use it.
It cannot be recovered. That is what encryption means. Store it somewhere safe before you close the tab.
It controls permissions such as printing, as opposed to opening. Leave it blank to reuse the same password.
This tool works entirely on this page. Your file is opened by JavaScript here, changed in memory, and handed straight back to you — it is never uploaded. Open your browser's Network tab while you use it and you will see nothing leave your device.
Because there is no server doing the work, there is no signup, no watermark, no file size limit, and no daily cap. Nothing is stored, because nothing is received.
Browse all free PDF tools, or read how we handle privacy and security.