Add password to PDF
Encrypt a PDF with AES-256 so that only people who know your passphrase can open it, optionally blocking printing, copying or editing.
Process locally
Files stay in this browser session. Closing or clearing releases them.
Choose files
PDF, one at a time
Drop files here, or
Adjust settings
Optional: Allow printing, Allow copying text and images, Allow editing, comments and forms
Run
Processes in this browser; cancel at any time
About this tool
Password-protect a PDF so that only people who know the password can open it. The file is encrypted with AES-256, the strongest method the PDF format offers, and opens in Adobe Acrobat, Apple Preview, Chrome, Edge and other current PDF readers once the password is entered.
You can also block printing, copying text and images, or editing. Encryption runs in your browser with qpdf compiled to WebAssembly: neither the PDF nor the password is uploaded, and the password is not saved with the page or with workflows.
How to use it
- Choose a PDF file, or drop it on the page.
- Type the “Password to set”. A long passphrase is best; it is needed every time the file is opened.
- Optionally turn off “Allow printing”, “Allow copying text and images” or “Allow editing, comments and forms”.
- Select Run, then download the protected PDF and open it once to check that it asks for the password.
Formats and limits
- Input
- PDF, one at a time; Text
- Output
- Size limit
- 80 MB
- Page limit
- 500 pages
- Settings
- Allow printing; Allow copying text and images; Allow editing, comments and forms
- Privacy
- Files stay in the current browser session. No file bytes are uploaded.
- Price
- Free, no sign-up
Common questions
How secure is the encryption?
The PDF is encrypted with AES-256, as defined in PDF 2.0 (security handler revision 6). Its strength depends on the password: a long, unique passphrase cannot practically be guessed, while a short or common one can.
What if I forget the password?
It cannot be recovered, here or anywhere else, because the password is never stored. Keep the original unprotected file, or keep the password in a password manager.
How do the printing and copying restrictions work?
When you turn a permission off, the PDF also gets a random owner password that nobody knows, so the opening password cannot lift the restriction. Readers that respect PDF permissions, such as Acrobat, then disable those actions; some programs ignore them, so treat restrictions as a request rather than a guarantee.
Why is my PDF refused?
A PDF that is already encrypted must be unlocked first, and digitally signed PDFs are refused because encrypting them would invalidate the signature. Damaged files, files over 80 MB and documents over 500 pages are refused with a message saying why.
Are my PDF and password uploaded?
No. Both stay in your browser. The password is used once to encrypt the file and is not kept with the page, its settings or workflows.
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