How to Password Protect a PDF (Free, Strong Encryption)
Open Protect PDFFree · works in your browser · no upload→Payslips, bank statements, medical reports and ID copies should be locked before you email them. A password-protected PDF can't be opened by anyone who intercepts or forwards the file without also knowing the password.
Lock a PDF in your browser
- Open Protect PDF and add your file.
- Type a password, then type it again to confirm.
- Press Protect PDF and download the locked file.
The file is encrypted with AES-256, the strongest standard PDF encryption, which every modern PDF reader supports. The encryption runs on your device, so neither the document nor the password is sent to us.
Many other PDFSorted tools (merge, split, compress, sign and more) also have a Protect with a password option, so you can lock the result in the same step.
On a Mac with Preview
Open the PDF, choose File → Export, tick Encrypt, enter a password and save.
Choosing a good password
- Use at least 10 characters. Length matters more than symbols.
- A short phrase of unrelated words (for example
river-lamp-orange-42) is strong and easy to type. - Don't use your date of birth or phone number. They're the first things an attacker tries.
Send the password a different way
If you email the PDF and the password in the same message, anyone who gets the email gets both. Send the file by email and the password by phone call, SMS or WhatsApp.
If you forget the password
There is no "reset" for an encrypted PDF. Nobody, including us, can recover the content without the password. Keep the original unlocked file somewhere safe, or store the password in a password manager.
Try Protect PDF nowAdd a password, free and private→