Lock PDF Free Online, Privately.
Create a password-protected copy in your browser. Your file and password stay on your device from start to finish.
Lock your PDF
Add password protection without uploading your file.
What does a PDF locker do?
A PDF locker encrypts a fresh copy of your document with a password. Anyone opening the protected copy will need that password before they can view it.
How to lock a PDF
The process is straightforward: choose a PDF, create and confirm a password, select any permissions you need, and download the protected copy. The tool works entirely in your browser — there is no account to create and nothing to install. For advice on choosing a strong password and deciding when protection is worth it, see our guide on how to password-protect a PDF.
Why lock PDFs in your browser?
Contracts, applications, invoices, and personal records can contain sensitive information. unlockpdf free processes the document privately with browser code, so your PDF and password are not sent to a server. If you want to understand why that matters, read why browser-based tools are safer.
Choose the method that fits your PDF
The default image-based method is broadly compatible and preserves the page appearance, but it may flatten selectable text, forms, annotations, and bookmarks. The optional direct-encryption method uses QPDF to protect the original PDF structure, which is better for feature-rich documents.
Choose optional permissions
You can allow printing and text copying, while leaving editing and forms restricted. PDF viewer applications may interpret permission settings differently, so use the open password as the primary protection — the distinction is explained in open vs. permissions passwords.
Free PDF protection, explained.
Find out how to add a password, restrict editing, and protect your PDF privately.
How do I lock a PDF for free?
Choose a PDF, create and confirm a password, select any printing, copying, editing, or forms permissions you need, and download the protected copy. The tool runs in your browser without an account, upload, or software installation.
How do I lock a PDF file with a password for free?
Open the free PDF locker, select your file, enter the password twice, and choose Lock PDF. The result is an encrypted PDF that asks for the password when someone tries to open it.
How can I lock a PDF from editing for free?
Create a protected copy and leave editing disabled in the permissions options. For stronger protection, use a long unique open password as well; PDF viewer applications may interpret permissions differently, so do not rely on an editing restriction alone.
How do I lock a PDF online without uploading it?
Use the browser-based lock tool on this page. Processing happens locally on your device, so the original PDF and the password are not sent to a remote server. Download the protected copy when processing finishes.
Which PDF locking method should I use?
Image-based locking is the default and is broadly compatible, but it may flatten selectable text, forms, bookmarks, and annotations. Direct encryption is better when you want to protect the original PDF structure and retain those features. Both methods are free and local.
Is it free to lock a PDF with a password online?
Yes. This tool creates a password-protected PDF at no charge, with no sign-up, watermark, or paid download step. Keep your password safe because it is not stored or recoverable by the tool.