Lock PDF

Password-protect PDFs instantly. Free, secure, private.

🔒 Drop your PDF here

or click to upload

About Lock PDF

Lock PDF File Online

The Lock PDF File Online tool allows you to protect a PDF document by adding a password. It helps prevent unauthorized access and ensures that sensitive or confidential information remains secure when sharing or storing PDFs.

Protect PDFs with a Password

Adding a password to your PDF helps control who can open and view the document. This is especially useful for files containing personal, business, or legal data.

Lock PDF files with a secure password
Prevent unauthorized viewing or access
Keep document content private
No changes to layout or quality

Simple and Secure Workflow

The locking process is quick and easy to follow:

Upload or drag-and-drop your PDF file
Enter and confirm a password
Apply password protection
Download the locked PDF file

The original document structure and formatting remain unchanged.

Why Lock a PDF?

Protect sensitive or confidential information
Secure financial, legal, or personal documents
Control access when sharing files online
Prevent accidental exposure of data
Add an extra layer of document security

Common Use Cases

Protecting invoices, reports, or contracts
Securing academic or research documents
Locking PDFs before email or cloud sharing
Storing confidential records safely
Sharing password-protected documents with clients

How It Works

After uploading a PDF, you set a password that is applied to the document. The file is then encrypted and made available for download. Only users with the correct password can open the locked PDF.

Privacy and Compatibility

Files are processed temporarily during the locking process and are not stored permanently. The locked PDF remains compatible with all standard PDF readers across desktop and mobile devices.

Also Try this Tool- Merge PDF Online – Combine Multiple PDF Files into One

FAQs

Is PDF Lock completely free to use?

Yes, absolutely! PDF Lock is 100% free with no hidden charges, subscription fees, or usage limits. You can password-protect as many PDF files as you need without any watermarks or restrictions.

Are my files stored on your servers?

No, we prioritize your privacy. Files are processed in temporary memory and automatically deleted from our servers immediately after encryption and download. We don’t store, analyze, or share your documents.

What encryption standard does PDF Lock use?

We use AES-256 encryption, which is military-grade security and the same standard used by banks and government agencies. This ensures your PDFs are protected with industry-best encryption technology.

Can I recover my PDF if I forget the password?

No, for security reasons, we cannot recover or reset passwords. The encryption is designed to be one-way. We strongly recommend keeping a backup of your original file or storing your password securely using a password manager.

Will the locked PDF work with all PDF readers?

Yes! Your encrypted PDF will work flawlessly with Adobe Acrobat Reader, Preview (Mac), Chrome PDF viewer, Foxit Reader, and all other major PDF applications that support standard PDF encryption.

What’s the difference between user and owner passwords?

User password (document open password) is required to view the PDF. Owner password (permissions password) controls what users can do – like printing, copying, or editing. Our tool sets both for maximum control.

Is there a file size limit for PDF Lock?

There’s no artificial file size limit. However, extremely large files (500MB+) may take longer to process depending on your internet connection. Most business and personal documents process in seconds.

Does PDF Lock work on mobile devices?

Yes! PDF Lock is fully responsive and works perfectly on smartphones and tablets. You can secure PDFs directly from your iOS or Android device using Safari, Chrome, or any modern mobile browser.

Can I remove password protection from a PDF?

This tool is specifically for adding password protection. To remove a password, you would need the original password and use a dedicated “PDF Unlock” tool. We don’t offer password removal services.

What should I do if the tool isn’t working?

First, ensure you’re using a modern browser (Chrome, Firefox, Safari, Edge). Clear your browser cache, disable ad-blockers for our site, and try again. If issues persist, contact our support team for assistance.

Disclaimer

Files uploaded to this tool are processed automatically and are not stored permanently on our servers. We do not view, share, or retain user data. Results are provided “as-is” and should be verified before use. pdftools.rajstudy.in is not responsible for any data loss or misuse.