Protect PDF

About this tool

This free Protect PDF tool adds a password to a PDF. Once it is protected, anyone who opens the file — in Acrobat, Chrome, Edge, Preview or on a phone — has to type that password first.

The file is encrypted with AES-128, the same standard encryption Acrobat uses, and it all happens in your browser. Your document and your password are never uploaded, so a confidential contract, payslip or report never leaves your computer.

Change the password on a protected PDF

Upload a PDF that already has a password and the tool spots it straight away: a Current password box appears above the new one. Type the password the file uses today, choose the new one, and download a copy that opens with the new password only — the old one stops working.

That is the quick way to change a PDF password when a document is being reissued, when someone who knew the old password has left, or when the password was shared over an insecure channel. You do need to know the current password: the tool changes a password you have, it does not crack or bypass one you don't. To take the password off altogether instead, use the Unlock PDF tool.

Restrict printing, copying and editing

Beyond the open password you can also decide what people are allowed to do with the document. Untick any action to block it:

• Printing — stop the PDF being printed
• Copying text and images — stop content being selected and pasted elsewhere
• Editing the content — stop changes to the text and graphics
• Adding comments — stop annotations and sticky notes
• Filling in forms — stop form fields being completed
• Adding, deleting or rotating pages — stop the document being reorganised

You can set a separate permissions password so that only you can lift those restrictions later, while everyone else opens the file with the normal password.

Features

• Add an open password to any PDF — AES-128 encryption
• Optionally restrict printing, copying, editing, comments, forms and page changes
• Optional separate permissions (owner) password
• Change the password on a PDF that already has one — in one step
• Password strength meter and a confirm field, so you don't lock yourself out of a typo
• Works fully in your browser — nothing uploaded, nothing stored
• No sign-up, no watermark, completely free

Common uses

• Send an invoice, contract or offer letter by email without it being readable by anyone who intercepts it
• Protect payslips, HR records or medical documents before sharing them
• Change the password on a shared document after someone leaves the team
• Lock a quotation or price list so the client can read it but not edit or copy the numbers
• Add a password to board papers or financial reports before they are circulated

Good to know

• Keep your password somewhere safe. Nobody — including this site — can recover or reset it. If the password is lost, the document is lost.
• To change a password you must know the current one; to remove a password altogether, use the Unlock PDF tool.
• Permission restrictions are honoured by mainstream readers, but they rely on the reader behaving. The open password is the part that really encrypts the file.

How to use it

• Upload the PDF — click the upload area or drag your file in
• If it is already protected — type its current password in the box that appears
• Choose a password — type it twice so a typo can't lock you out
• Restrict actions (optional) — open the extra options and untick printing, copying or editing
• Protect & download — click the button, then Download to save the encrypted copy