Password Protect a PDF for Free Online
Add a password to a PDF, encrypted with AES-256.
Select a PDF to protect
Click to choose, or drop a file here
You can also paste (Ctrl+V / Cmd+V)
Most tools run entirely on your device
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About password-protecting a PDF
Adding a password means the file can't be opened without it — a basic layer of protection when emailing something confidential or storing it in shared cloud storage.
The encryption is applied in your browser and the protected file is what you download; the password is never sent anywhere. Keep a copy of the password somewhere safe, because a protected PDF genuinely cannot be opened without it, and share it through a different channel from the file itself.
Adding a password means the file can't be opened without it — a basic layer of protection when emailing something confidential or storing it in shared cloud storage. Keep a copy of the password somewhere safe: a protected PDF genuinely cannot be opened without it.
Supported files
Accepts a single PDF. Produces a password-protected (encrypted) PDF.
Is my file uploaded?
No. Encryption is applied in your browser and the protected file is what you download; the password is never sent anywhere.
Common problems
- I forgot the password
- There's no recovery — that's the point of encryption. You'll need the original unprotected file.
- The recipient can open it without typing the password
- Their PDF reader may have cached the password from a previous open. It's still encrypted; ask them to open it in a private window to confirm.
How to Protect PDF
- 1
Open the tool
Open the Protect PDF tool and drop your file onto the page, or click to browse for it. Everything runs in your browser — the file is never uploaded.
- 2
Set a password
Type the password you want to require to open the file.
- 3
Encrypt and download
Click Protect and download the AES-256 encrypted PDF.
Further reading
Protect PDF — frequently asked questions
What encryption does this actually use?+
AES-256, the current PDF encryption standard — the same class of encryption Adobe Acrobat and other professional tools use, applied entirely in your browser via the Web Crypto API.
Can I recover the password if I forget it?+
No — there's no recovery mechanism, by design. That's what makes the encryption real. Keep the password somewhere safe; if it's lost, the file can't be opened by anyone, including you.
Is there a free way to password protect a PDF online?+
Yes — this tool encrypts a PDF with AES-256 entirely in your browser, free and with no upload.
Can I also restrict printing or copying, not just require a password?+
This tool focuses on the open password — requiring a password just to open the file — since that's the strongest, most universally respected protection. Permission restrictions like disabling copying are easily bypassed by other software, so they're not the focus here.
Do you upload my files to a server?+
No — every tool here processes your files entirely on your device, and nothing is uploaded to a server. The only exception is the AI tools, which send the extracted text (not the file) to Claude to do their work.
Is there a file size limit?+
There's no artificial limit we impose, but since processing happens in your browser, very large files (500+ MB or 1,000+ pages) are limited by your device's memory rather than by us.
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