Password protect a PDF
Some documents should only be read by the people they are meant for: a contract before it is signed, a payslip, a medical letter, a scan of your passport. Protecting a PDF encrypts it with a password, so the file opens only for someone who types that password, in any PDF reader on any device. We use 256-bit AES, the strongest encryption the PDF format defines. The whole job happens in your browser. Your document is never uploaded, and neither is your password: both stay on this device, and we never see either of them. That also means we cannot recover a forgotten password, so choose one you will remember or keep it somewhere safe. The tool works on PDF files up to 50 MB, which covers almost every document people want to protect, and it does not change anything else about the file.
Drag your files here
How it works
Choose your PDF
Drag it onto the page or use the file picker. It is opened here, in your browser, and not uploaded anywhere.
Type a password twice
The second time guards against a typo, which would leave you with a file you cannot open. Tick Show password if you want to see what you typed.
Download the protected file
Press Protect PDF and download the result. Anyone who opens it, including you, will be asked for the password.
Frequently asked questions
- Is my password sent to your servers?
- No. The encryption runs in your browser, so neither the document nor the password leaves your device. There is nothing on our side to store, log or leak.
- How strong is the protection?
- The file is encrypted with 256-bit AES, the strongest method the PDF standard defines. How safe it is in practice depends mostly on the password: a long phrase is far harder to guess than a short word.
- Can you recover a password I have forgotten?
- No. We never see it, and a properly encrypted PDF cannot be opened without it. Keep the original unprotected copy, or store the password somewhere safe.
- Why is there a 50 MB limit?
- Our other tools send files over 50 MB to our servers. Doing that here would mean sending your password too, so this tool stays in your browser and keeps to what a browser can handle.
- My PDF already has a password. Can I change it?
- Yes, in two steps: remove the old password with Unlock PDF, then set the new one here.