Password Protect PDF Online Free
Lock your PDF file with custom secure password encryption. Encryption is computed locally on your device.
Drag & drop a PDF file here or click to browse
PDF documents up to 100MB · 100% Private, client-side only
Add password to PDF with local encryption
Protect PDF files with password encryption computed entirely in your browser. Set a strong passphrase, confirm it, and download a locked document that requires the password to open. Your file never leaves your device during encryption.
Use this password protect PDF free tool before emailing tax forms, legal agreements, or internal reports. Industry-standard PDF security keeps content protected from unauthorized access while you retain full control of the password.
Need to remove a lock later? Use unlock PDF with the correct password. Combine with sign PDF and redact PDF for a complete secure workflow.
Protect PDF from copying and editing
Secure PDF online without software
How to password protect a PDF
Encrypt your PDF with a secure password online — free and private. Add AES password protection so only people with the correct passphrase can open the document. Encryption runs locally in your browser.
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Upload the PDF to protect
Add the PDF file you want to lock. The document is never transmitted to any server.
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Set a strong password
Enter and confirm your PDF password in the security settings panel. Use a passphrase you can share securely.
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Encrypt locally
Click Protect PDF to apply AES encryption. The password is embedded in the file using industry-standard PDF security.
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Download the locked PDF
Save the encrypted document. Recipients will need your password to open it in any PDF reader.
BrainyPDF processes every file locally in your browser. No uploads, no cloud storage, no account required — a privacy-first alternative to server-based PDF tools.
Free PDF password protection — frequently asked questions
Answers about encrypting PDFs with a password online for free, security, and related lock/unlock tools.
How do I password protect a PDF for free?
Upload your PDF, enter and confirm a strong password, then click Protect PDF. BrainyPDF applies AES encryption locally in your browser and downloads the locked file — free with no account required.
How do I add a password to a PDF online?
Type your chosen password and confirmation in the sidebar, then click Protect PDF. The encrypted output requires that password to open, view, or print the document.
How do I lock a PDF with a password without software?
Open BrainyPDF in any modern browser, upload your PDF, set a password in the sidebar, and download the encrypted file. No desktop app or browser extension is needed.
How do I protect a PDF from editing and copying?
Password encryption restricts access to the entire document. Recipients need the password to open the PDF. For removing visible sensitive content before sharing, combine with the free redact PDF tool.
Is it free to password protect a PDF with no account?
Yes. BrainyPDF is a completely free PDF encryption tool with no sign-up, subscription, or daily limits. Protect as many documents as you need without watermarks.
Do I need an account to password protect a PDF?
No account is required. Upload your PDF, set a password, and download the encrypted file immediately. Your password is never sent to a server.
Is it safe to password protect a PDF online?
Your files are never uploaded. Encryption runs entirely in your browser using industry-standard AES, so contracts and financial statements stay on your device throughout the process.
How do I password protect a PDF on Mac or iPhone?
Open BrainyPDF in Safari or Chrome on your Mac, iPhone, or iPad, upload the PDF, and enter your password. Encryption happens locally with no app installation needed.
How strong is PDF password protection?
BrainyPDF uses industry-standard PDF password encryption (AES). Choose a strong, unique passphrase with mixed characters for the best protection. Combined with local processing, this is suitable for sensitive documents.
Can I remove a PDF password later for free?
Yes, if you know the password. Use the free unlock PDF tool to decrypt the file and download an unprotected copy for editing or printing.