PDF TOOLS
Encrypt PDF — Add a Password to a PDF (Free)
Password-protect a PDF so it can't be opened without the password. Runs in your browser for free — the document is never uploaded to a server.
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Drop a file here or click to choose
One PDF file — protected with a password you choose
Lock a PDF with an open password: anyone who opens the protected copy has to type it first. The encryption runs entirely in your browser with pdf-lib, so both your file and the password you choose stay on your device — a protected file is created without your contents passing through any server.
Because the password is only used locally to encrypt the file, it's never stored or recoverable. If you forget it, that copy is inaccessible — so keep the original unprotected file somewhere safe.
How to use it
- Open the PDF you want to protect.
- Type the password that will be required to open it.
- Encrypt the file and download the password-protected copy.
Troubleshooting
- A recipient's viewer won't accept the password.
- The tool applies standard PDF encryption that mainstream desktop and mobile readers honour. If a very old or non-standard viewer struggles, opening the file in a current reader (Acrobat, a modern browser) resolves it.
- You need to stop copying or printing, not just opening.
- This adds the open password that gates access to the document. Fine-grained permission controls (blocking copy or print for people who can already open it) are a separate feature and aren't the focus here.
Frequently asked questions
- What happens if I forget the password?
- There's no recovery. The password isn't stored anywhere — it's only used to encrypt on your device — so if you lose it, you lose access to that copy. Always keep the original unprotected file.
- Is my file or password sent to a server?
- No. Encryption happens in your browser with pdf-lib, so both the PDF and the password stay on your machine. Nothing about the file is transmitted.