Password protect a PDF online, free
Lock a PDF so it can only be opened with a password. Uses AES-256 encryption.
How to use Protect PDF
- Choose the PDF you want to lock.
- Type a password, then type it again to confirm. Keep it somewhere safe, because nobody can recover it for you.
- Press Protect PDF.
- Download the locked PDF. Anyone who opens it, in any PDF reader, will be asked for the password. It is worth doing for anything you send by email, like salary slips or contracts.
Protect PDF: common questions
What if I forget the password?
Nobody can recover it, ScalePDF included, because it is never sent anywhere. Keep it somewhere safe.
Is there a limit on how many PDFs I can protect?
No. There is no daily or monthly limit and no account, and it stays free for life: use it as often as you like. Files up to 50 MB in all are processed on ScalePDF’s server; bigger ones are processed right on your device, which can take a little longer.
Is my file uploaded?
Only while it is being processed. Your file goes to ScalePDF’s server over an encrypted connection, is worked on in memory, and is deleted the moment the result comes back. Nothing is stored, logged or shared.