Protect PDF with Password Free Online

How to Password Protect a PDF

Upload your PDF

Drag and drop your PDF file or click to select it from your device. Your file stays in your browser — nothing is uploaded to any server.

Set a password

Enter the password you want to use to protect the PDF. Anyone who wants to open the file will need this password.

Download your protected PDF

Click "Protect PDF" and download the encrypted file. The original file remains unchanged.

Why use FyleTools to protect your PDF?

100% Private

Your files never leave your device. All encryption happens in your browser using WebAssembly — no server uploads, no third-party access.

Free & Unlimited

No registration, no file limits, no watermarks. Protect as many PDFs as you need, completely free.

Universal Compatibility

Protected PDFs work with all major readers including standard PDF readers, Chrome, Firefox, Edge, and Preview on Mac.

Frequently Asked Questions

Is my PDF uploaded to a server?

No. FyleTools processes everything directly in your browser using WebAssembly technology. Your file never leaves your device, making it completely safe for sensitive documents.

What type of encryption is used?

FyleTools uses standard PDF password encryption (RC4, 40-bit), which is compatible with all PDF readers. This prevents unauthorized users from opening the file without the password.

Can I remove the password later?

Yes. Use our Unlock PDF tool with the same password to remove the protection and get an unencrypted version of your document.

Is there a file size limit?

There is no fixed limit. Since processing happens entirely in your browser, the maximum file size depends on your device's available memory. Most devices handle files up to 100 MB without issues.

How strong is the password protection?

The PDF is encrypted so that opening the file requires the exact password you set. Use a strong, unique password for maximum security.

Does this work on my phone?

Yes. The tool runs entirely in your browser on any device. Your PDF and password never leave your device.

Can I protect multiple PDFs at once?

Currently the tool protects one PDF at a time. Upload each file individually to apply password protection.

Can I protect a PDF with different passwords for opening and editing?

Currently the tool sets a single password required to open the PDF. For separate owner/user passwords, dedicated PDF security software may be needed.

Will the protected PDF work in Google Drive or Dropbox?

Yes. The password-protected PDF is a standard encrypted file. Cloud services will store it, but anyone accessing it will need the password to view its contents.

Can I password-protect a scanned PDF?

Yes. Password protection works on any PDF regardless of whether it contains text, images, or scanned pages. The entire file is encrypted.

Is there a way to batch-protect multiple PDFs at once?

The tool processes one PDF at a time. Upload each file individually and set a password for each document separately.

When to Use This Tool

Protect confidential business documents before sharing via email

Secure personal tax returns and financial statements

Lock legal contracts so only authorized parties can open them

Add a password to medical records or insurance documents

Format	Description	Best For
PDF 1.4+	Standard PDF with password encryption	Universal compatibility with all readers
PDF/A	Archival PDFs can be protected	Long-term secure document storage

Tips & Best Practices

Use a strong password with at least 8 characters, mixing letters, numbers, and symbols

Store the password separately from the PDF — if you lose it, the file cannot be recovered

Always keep an unprotected backup copy in a secure location

Test opening the protected PDF in different readers to confirm compatibility

How It Works — 100% Private Processing

FyleTools encrypts your PDF entirely in your browser using WebAssembly and the lopdf library compiled from Rust. Your document and password are never sent to any server — the encryption algorithm runs locally on your device. This means confidential contracts, financial records, and personal files stay completely private throughout the process.