How to Password Protect a PDF on Mac (Free, Without Acrobat)
Add password protection to a PDF on Mac using your browser or Preview. Secure PDFs for free without Adobe Acrobat.
Mac users have two good options for password-protecting PDFs: the built-in Preview app and FixMyPDF's browser-based protect tool. Both are free and require no Acrobat. The difference is in how much control you get and whether you need owner permission restrictions in addition to an open password.
Method 1: Preview (Quick, Built-In)
Open your PDF in Preview. Go to File → Export as PDF. In the export dialog, check "Encrypt" and enter a password. Click Save. This adds an open password — anyone who wants to view the PDF must enter this password. It's quick for simple password protection but offers limited control over permissions.
Method 2: FixMyPDF Protect Tool (More Control)
Go to fixmypdf.in/tools/protect in Safari or Chrome. Upload your PDF, enter a password, and choose permission restrictions: prevent printing, copying, editing, or form filling. This gives you both an open password and fine-grained control over what recipients can do with the document.
Owner Password vs User Password
A User password (open password) prevents opening the file without the password. An Owner password (permissions password) lets people open the file but restricts what they can do. Our protect tool lets you set both independently — useful for documents you want people to read but not copy or print.
How Strong Is the Encryption?
Our tool uses 128-bit or 256-bit AES encryption, the same standard used by Adobe Acrobat. A document encrypted with AES-256 and a strong password is mathematically infeasible to brute-force with current technology. Use a long, unique password for maximum security.
Tips for a Strong PDF Password
Use at least 12 characters combining uppercase, lowercase, numbers, and symbols. Avoid dictionary words or personal information. Use a password manager to generate and store the password — if you lose the password to an AES-256 encrypted PDF, recovery is not realistically possible.
Privacy During Encryption
Your PDF and password are processed entirely in your browser on your Mac — no data is sent to FixMyPDF servers. The encryption happens locally using WebCrypto API, a native browser cryptography standard. Your sensitive document and chosen password never leave your device.
After Password Protecting
Test the protected PDF by opening it in a new browser tab or in Preview — you should be prompted for the password. If you need to remove the password later, use our unlock tool. You can also compress the protected PDF — compression works before or after encryption.
Try Protect PDF Now — Free
Browser-based, private, and instant. No account or software required.
Open Protect PDF