Add a Password to Your PDF
Password protect a PDF online for free, no upload and no account. AES-256 encryption, optional printing and copying locks, works with your WiFi off.
Drop PDF files here
or
Max 25 MB per file · Secure and private, files are never stored
How it works
- 1Drop the PDF you want to protect into the box
- 2Type a password, then type it again to confirm
- 3Click "Protect PDF", encrypted in your browser with AES-256
- 4Download the protected PDF; keep the password somewhere safe
What this tool does
This page locks a PDF with a password, so nobody can open it without typing that password first. The file is encrypted with AES-256, the strong standard the PDF specification itself recommends. Everything happens inside your browser: the document is read from your computer, locked there, and saved straight back to your downloads.
Your password never leaves your device
Every big-name protect tool asks you to upload the document and its new password to their servers, then asks you to trust their storage rules. Here there is nothing to trust: the password is typed in your browser and used in your browser, so it cannot leak because it never travels. Turn off your WiFi and it still works.
What the password protects, and what it does not
The open password is strong: without it, the contents are unreadable. The optional permission switches (printing, copying, editing, form filling) are respected by normal readers like Adobe Reader, Preview and browsers, but they are not unbreakable DRM, a determined tool can strip them. Use them to set expectations, not to guard secrets. And one promise to remember: there is no password recovery. A lost password means the file stays locked forever.
Pick a password people cannot guess
Names, birthdays and 123456 are cracked in seconds. Four or more random words, like river-lantern-coffee-north, are easy for you to remember and hard for a computer. Never reuse the password from your email or bank, and send the password on a different channel than the file: file by email, password by message.
Need a different result?
Received a locked PDF and know its password? Unlock PDF removes it and saves a clean copy. To shrink a large PDF before protecting it, use Compress PDF. To put several documents into one file first, use Merge PDF.
Frequently asked questions
How do I password protect a PDF for free?
Drop the PDF on this page, type a password twice, and click Protect PDF. The encrypted file downloads straight away. It is completely free, with no account, no watermark and no daily task limit, because the work happens on your own computer.
What happens if I forget the PDF password?
The file cannot be opened again, by anyone. AES-256 has no back door and this page has no recovery, which is exactly what you want from a lock. Keep the password in a password manager or write it down somewhere safe before you send the file anywhere.
Will the protected PDF open in Adobe Reader and Preview?
Yes. The file uses standard PDF encryption, so Adobe Reader, Acrobat, macOS Preview, browsers and most phone readers all ask for the password and open it normally. Recipients do not need to install anything to use the password you sent them.
Does this tool work if I turn off my WiFi?
Yes. Turn off your WiFi, this tool will still run 100% locally. Once the page has loaded, the encryption happens on your own computer and the protected file is saved straight to your downloads, no connection needed.
Can I remove the password again later?
Yes, while you still know it. Open the file on Unlock PDF, type the same password, and it saves a clean, unprotected copy. That page also removes printing and copying restrictions from files that open without a password.