Password Protect PDF for Free
Add a password to your PDF in seconds — 100% private, no upload.
Drag & drop a PDF file here
or browse
Password Protect PDF adds an open password to a document, so anyone trying to view it is prompted to enter it first — useful before emailing a contract, payslip, or ID scan. It uses the PDF Standard Security Handler with 128-bit RC4 encryption, the same standard Adobe Acrobat and most PDF viewers already support, so the protected file opens normally everywhere without a special app. An optional owner password can also be set to restrict copying and editing.
What you can do
- An Open Password that must be entered before anyone can view the file.
- An optional, separate Owner Password to restrict copying and editing.
- 128-bit RC4 encryption through the PDF Standard Security Handler, which Acrobat, Preview and other mainstream viewers support.
- A Confirm Password field, so the two entries must match.
How it works
- 1Drop your PDF onto the page.
- 2Enter a password in the Open Password field.
- 3Re-enter it in Confirm Password — they must match.
- 4Optionally click Show advanced options to set a separate Owner Password.
- 5Click Process File, then Download to save the encrypted PDF.
Why use SmilingPDF for this
- Encryption happens in your browser — the password and the PDF's contents are never sent anywhere.
- Standard 128-bit RC4 protection opens correctly in Adobe Acrobat, Preview, and other mainstream viewers, not just this site.
- No watermark, no server-imposed page limit, and no account needed to use it.
Private by design
Your file stays on your device.
- No upload
- No server storage
- No account required
- Browser-based processing
- No watermark
This tool runs inside your browser tab. Your file is read from your device, processed there, and handed back as a download — it is never sent to a SmilingPDF server, so there is nothing for us to store, read, or lose. You can check for yourself: open your browser's developer tools, switch to the Network tab and run the tool. Like most sites, SmilingPDF uses Google Analytics to count visits and which tools are used; that never includes the contents of your files. The privacy policy lists everything the site does collect.
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FAQ
Frequently asked questions
Got questions? We've got answers.
Is password protection secure?
Yes. We use 128-bit RC4 encryption (PDF Standard Security Handler, Revision 3) — the industry-standard for PDF open-password protection. The encryption happens entirely in your browser; your file is never uploaded.
Will the password work in all PDF viewers?
Yes. The encryption standard used is supported by Adobe Acrobat, Preview (macOS), browsers, and virtually all modern PDF viewers.
What happens if I forget the password?
There is no way to recover a forgotten password. Keep a backup of the unprotected PDF in a safe place before encrypting.
What does the owner password do?
It sets a second password that is separate from the one needed to open the file. The permissions written into the PDF are a fixed set — printing is allowed, copying and editing are restricted — and there are no per-permission toggles yet, so the owner password governs that fixed set rather than one you choose.
Is there a file size limit?
SmilingPDF imposes no limits. Everything runs in your browser, so it depends on your device memory.