Free PDF Password Protect Tool — Lock a PDF in Your Browser

Adding a password to a PDF is a common step before emailing a document that shouldn't be opened by just anyone — a salary slip, a personal ID scan, a contract draft, or internal notes shared with a small group. This tool locks a PDF with a password of your choosing, entirely inside your browser, so the file itself never has to be uploaded anywhere to get protected.

An Honest Note on What "Protection" Means Here

It's worth being direct about this rather than just slapping a padlock icon on the page: official, most widely-trusted PDF libraries for JavaScript (including the one this site uses for merging and splitting PDFs) don't support encryption at all — building real password protection into a browser tool required using a smaller, community-maintained library instead. That library does implement genuine PDF standard encryption, not a fake visual lock, and the password really is required to open the resulting file in PDF readers that respect PDF security. But it's a less battle-tested piece of software than the primary libraries used elsewhere on this site, so treat this as solid protection against casual snooping or accidental exposure — not as a guarantee suitable for documents where a security failure would be genuinely serious. For that level of need, consider dedicated, professionally audited PDF security software.

How to Use This Tool

Upload your PDF, choose a password (and confirm it), and decide whether you want to allow printing and text copying once someone enters the correct password. Click "Protect PDF" and download the resulting password-locked file. Anyone opening it in a PDF reader — Adobe Acrobat, Preview, browser PDF viewers, and most mobile PDF apps — will be prompted to enter your password before the content becomes visible.

Choosing a Good Password

Pick something the intended recipient can be told separately (over a phone call or a different message thread than the one carrying the file itself) rather than something guessable from context, like a birthday or the recipient's name. A password that's shared through the exact same channel as the protected file itself defeats much of the purpose, since anyone intercepting the file would likely see the password too.

Common Use Cases

Emailing salary slips, offer letters, or HR documents that shouldn't be casually forwarded, protecting scanned ID or KYC documents before sharing them with a specific recipient, locking draft contracts during a negotiation so only the intended party can open them, and adding a basic layer of protection to personal documents stored or shared online.

Privacy and Cost

The entire process — reading your PDF and applying the password — happens locally in your browser; your file and your chosen password are never sent anywhere. There's no sign-up, no watermark, and no daily usage limit.

Frequently Asked Questions

Is this as strong as paid PDF security software?

It implements the real PDF standard encryption method, but the underlying library is community-maintained rather than a widely-audited commercial product. For routine confidentiality — keeping a document from being casually opened by the wrong person — it does the job. For documents where a security failure would carry serious consequences, use dedicated, professionally audited software instead.

What happens if I forget the password?

There is no recovery option — if you forget the password, the protected PDF cannot be reopened by this tool or any other, short of specialized password-cracking software. Always keep your unprotected original file somewhere safe in case you need it again.

Can I remove a password from a PDF using this same tool?

This tool only adds password protection. To remove a password from an already-protected PDF, use a separate PDF unlock/password-remove tool (you'll need to know the existing password to unlock it).

Will the password protect against someone editing the PDF?

The password itself controls whether the file can be opened at all. The separate "Allow Printing" and "Allow Copying Text" settings control what someone can do once they've entered the correct password and opened the file — but these restriction flags, like most PDF permission settings, are enforced by the PDF reader's cooperation rather than being an unbreakable technical barrier, so treat them as a deterrent rather than an absolute guarantee.