Password Protect PDF Online — Free & Secure
Add password protection to PDF files online for free. Encrypt your documents with RC4 128-bit security — 100% browser-based, no upload needed.
Add password protection to any PDF file for free — no signup, no watermarks, no software to install. PDFFlare encrypts your document directly in your browser so the file never leaves your device. Set a strong password and download a protected PDF that cannot be opened without it.
Sensitive documents — tax returns, contracts, medical records, financial statements — should never be shared without protection. Adding a password ensures that only people who know the password can view the contents, even if the file is intercepted or forwarded to the wrong person. PDFFlare uses standard PDF encryption that is recognized by every PDF reader.
Need to remove a password later? Use our Unlock PDF tool. Want to compress the file before encrypting? Try Compress PDF first to reduce the file size.
Drop your PDF file here
PDF up to 50 MB
How to Password Protect PDF Files
Upload your PDF file
Click the upload area or drag and drop a PDF file you want to protect. All standard PDF formats are supported.
Enter a strong password
Type a password and confirm it. Use a mix of uppercase, lowercase, numbers, and symbols for the best security.
Encrypt and download
Click 'Protect PDF' to encrypt your document. The password-protected PDF is downloaded instantly — no server upload required.
Store your password safely
Save your password in a secure location. Without it, the PDF cannot be opened. PDFFlare does not store or recover passwords.
When Do You Need to Password Protect a PDF?
Sharing sensitive financial documents: Tax returns, bank statements, and invoices contain personal information that should be encrypted before emailing. Add a password and share the password separately via a different channel.
Protecting legal contracts: Before sending a contract or NDA via email, encrypt it so only the intended recipient can open it. This adds a layer of security in case the email is forwarded or intercepted.
Securing medical and personal records: Medical records, insurance documents, and identity documents should always be password-protected when stored on shared drives or sent electronically.
Restricting access to confidential reports: Internal business reports, strategy documents, and employee records can be encrypted so only authorized team members with the password can access them.
Why Use PDFFlare to Password Protect PDFs?
100% Browser-Based Encryption
Your PDF files never leave your computer. Encryption runs entirely in your browser using pdf-lib — no server uploads, no third-party access.
Password Strength Feedback
A real-time strength indicator helps you choose a secure password. See whether your password is weak, medium, or strong before encrypting.
No Quality Loss
Password protection is added at the document level. Text, images, fonts, and formatting stay exactly as they are — zero re-encoding or compression.
No Signup Required
Start encrypting immediately — no account, no email, no watermarks. Just drop your file, set a password, and download the protected PDF.