Protect PDF

Add a password to your PDF to keep it secure

Drop your PDF here

or click to browse — Max 50 MB

Protect PDF with Password — Free Online PDF Locker

Skilltosky PDF Tools lets you password protect PDF files for free, directly in your browser. Enter a user password to restrict opening the document and an optional owner password to control printing and editing permissions. Whether you need to encrypt PDF files for sharing sensitive contracts or simply want to add a password to a PDF before emailing it, our free PDF locker gets it done in seconds — no account, no server upload.

Step-by-Step Guide

  1. Upload your PDF — Drop your PDF onto the page or click to browse. Your file is read locally and never leaves your device.
  2. Enter your passwords — Type a user password (required) that recipients must enter to open the file. Optionally set a separate owner password to control print and edit permissions.
  3. Choose export quality — Select Medium, High or Ultra quality. Pages are rendered to canvas, then re-assembled into a new encrypted PDF using jsPDF.
  4. Download the protected PDF — Click Protect PDF and your password-protected file downloads instantly to your device.

Key Features

User & Owner Passwords

Set a user password to require before opening, and a separate owner password to restrict printing and editing permissions.

AES Encryption via jsPDF

The resulting PDF is encrypted using jsPDF's built-in encryption so only recipients with the correct password can open it.

Three Export Quality Levels

Choose Medium (108 DPI), High (216 DPI, recommended) or Ultra (324 DPI) to balance file size against output sharpness.

100% Private — No Upload

Everything happens inside your browser. Your PDF and passwords are never transmitted to any server.

Frequently Asked Questions

How do I password protect a PDF for free?

Upload your PDF, enter a user password (and optionally an owner password), choose an export quality and click Protect PDF. The encrypted file downloads instantly — no account or software needed.

What is the difference between user and owner passwords?

The user password is required to open and read the PDF. The owner password controls permissions such as printing and editing. If you only set a user password, the same password is used for both.

Will the protected PDF work in Adobe Reader and other viewers?

Yes. The resulting PDF uses standard password-based encryption that is recognised by Adobe Acrobat, Reader, Preview on Mac, and most other modern PDF viewers.

Can I protect a scanned or image-heavy PDF?

Yes. All pages are rasterised to canvas before being written into the encrypted PDF, so the tool handles any PDF regardless of content type.

Is there a file size limit?

Because the entire process runs in your browser there is no server-imposed size limit. Very large PDFs may take a little longer on lower-spec devices.

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