What this is for
A PDF you can already open, that asks for the password every single time. Bank statements, payslips, insurance documents and utility bills are routinely sent locked with a password built from your date of birth or the last digits of an account number. Once you have opened it, being asked again on every read, print and attach is just friction.
This removes the password from a copy. Everything happens in this browser tab.
What it is not
It is not a password cracker, and it will not become one. It decrypts a document using the password you type. Without the right password it fails, immediately, and makes no attempt to guess.
Saying that plainly is deliberate. Tools in this category attract people hoping for something else, and the ones that quietly encourage it end up with the wrong users and the wrong reputation.
The bug that this tool would otherwise have
Worth stating, because it explains a design decision you would otherwise never notice.
The underlying engine does not fail when the password is wrong. It prints an error, and then writes a small, blank, one-page document anyway. A tool that simply handed you whatever came out would tell you it had succeeded and give you a destroyed file — and if you had already deleted the original, that would be the end of it.
We measured that behaviour, and the tool now watches specifically for it. A wrong password produces a clear message and saves nothing at all.
After the password is gone
The saved copy opens without a password. That is what you asked for, and it also means anyone who gets hold of it can open it.
If it is a bank statement, it is now a bank statement anyone can read. Keep it somewhere you are content for it to be readable, and think twice before emailing it or leaving it in a downloads folder on a shared machine.
Two passwords, one document
PDFs can carry two: a user password that opens the document, and an owner password that controls printing and copying. The one to type here is the one that opens it.
If your PDF opens with no password but refuses to let you print, there is no password to remove — those are permission flags, and they are a different thing.