Protect PDF Converter
Password-protect a PDF online for free, directly in your browser. Set a password so the file can't be opened without it — no upload or signup required.
Drop your file here
or choose a file
Supports PDF
Your files are processed locally in your browser and are not uploaded to our servers.
How to use the Protect PDF converter
- 1
Drop a PDF onto the upload area, or click it to choose one.
- 2
Enter a password and confirm it — use the eye icon to check what you typed.
- 3
Click "Protect PDF." Encryption happens entirely in your browser.
- 4
Download the protected PDF — it will now prompt for that password when opened.
Common uses
- Adding a password before emailing a sensitive document
- Protecting a contract, invoice, or personal record you're sharing
- Keeping a shared file private until the intended recipient enters the password
Supported formats and limitations
Accepts PDF, up to one file at a time.
- This uses 128-bit RC4 encryption (PDF's classic "Standard Security Handler," compatible with virtually every PDF reader), not the newer AES-256 — strong enough to require the password to open the file, but not the most modern cipher available in some paid tools.
- This tool only gates opening the file — it doesn't apply separate restrictions on printing, copying, or editing once someone has the password.
- If you lose the password, there's no way to recover the file — nothing is stored anywhere, including by this site.
- One PDF at a time, up to 40 MB.
Frequently asked questions
No. Your files are processed in your browser and never uploaded. Encryption happens entirely on your device using pdf-lib and Web Crypto.
128-bit RC4, the PDF "Standard Security Handler" used by Acrobat 6 and every PDF reader since. It's a real, effective password lock, though not the newest AES-256 cipher some paid tools offer.
There's no recovery — the password isn't stored anywhere, by this site or anyone else. Keep it somewhere safe.
No — it only requires a password to open the file. It doesn't apply separate printing, copying, or editing restrictions.
Yes, 40 MB.