Lock PDF

Password-protect a PDF. Free, no signup required.

Encrypted & auto-deleted in 1 hour

This conversion requires server processing. Your file is encrypted in transit and automatically deleted within 1 hour.

Your files stay on your device — nothing is uploaded

How It Works

Upload the PDF you want to protect

Enter a password in the field

Download your password-protected PDF

Files encrypted in transit. Processed in isolated containers. Deleted within 1 hour.

Upload from any browser on desktop or mobile.

Priority queue for Pro users. Most files processed in seconds.

What kind of protection does this add?

It sets an owner password that restricts editing, printing, and copying. Recipients will need the password to open the PDF.

Is my PDF uploaded to a server?

No. Everything runs in your browser using pdf-lib. Your PDF and password never leave your device.

Can I remove the password later?

Yes. Use the Unlock PDF tool on OneConvertly — enter the password and download an unlocked copy.

Can I lock a PDF on my phone?

Yes. OneConvertly works in any modern mobile browser including Safari on iPhone and Chrome on Android.

Is there a file size limit?

Files up to 200MB are supported. Processing speed depends on your device since encryption runs locally.

Is this tool free?

Yes, completely free. No signup, no watermarks, no daily limits.