How do I remove the password from a PDF I own?

Maybe it's a bank statement that asks for your date of birth every time you open it, a payslip locked by a payroll system, or a contract a colleague protected two years ago. It is fine to unlock any of these, and typing the password every time gets tiring.

Whether you can do it comes down to one question.

The question that decides it

Can you already open the file?

If yes, removing the password is easy. If the file opens, the content can be unlocked, and once unlocked it can be saved again without the lock. Having the password means you have the key.

If no, it can't be done. A tool can only guess passwords. Modern PDF encryption is AES-256, and guessing takes far too long to ever finish.

So if you know the password, it's easy. If you forgot it, ask whoever made the file. That is what encryption is for.

Two different things called a password

This confuses even more people, because the same word covers two separate features.

The open password, sometimes called the user password, encrypts the content. Without it there is no readable document at all. This is real protection.

The permissions password, or owner password, doesn't stop the file opening. It marks the document as not to be printed, copied or edited, and readers that follow those settings disable the matching buttons.

Nothing forces a reader to follow the second kind. The content isn't protected. The reader app chooses to respect the setting. That is why a file you can read perfectly well can still refuse to let you copy a sentence out of it.

Removing it

Unlock PDF handles both cases. Give it the file, and the password if the file asks for one, and it writes a fresh copy with the encryption and the restrictions gone.

What you get back is a normal PDF with the same pages, text, images and quality. The pages are copied across as they are, so nothing gets worse. It opens without asking for a password.

When you should keep the password

Think about this before you remove it.

The password is doing a job on anything containing financial details, identity documents, medical information, or somebody else's personal data. An unlocked copy in a downloads folder, on a shared drive, or in a mail thread is a different risk from the encrypted original.

A reasonable middle path: unlock a working copy, keep the protected original, delete the working copy when you are done. And if you are sending it on to someone who does need protection, Protect PDF puts a new password on with encryption you choose.

The awkward case: it is not your file

If the document belongs to somebody else and you don't have the password, ask them. There is no technical way around that, and there shouldn't be.

If the document is yours but the sender set the password (a bank, an employer, a government portal), they will usually tell you the pattern. It is very often a fixed rule: date of birth in a particular format, the last digits of an account or identity number, a customer reference. Their help pages state it.

What removing the password does not change

People often think these two things change too. They don't.

A signature stays valid, but only if you change nothing else. Decryption alone does not alter the page content. Editing after unlocking does, and that will invalidate a signature.

Metadata is unchanged. Author, creation software and title survive. If you wanted to remove identifying details, that is a separate job. Check it, because it is easy to assume the unlock did it.

Where the password usually comes from

If the file is one you receive regularly rather than one you made, the password is almost always generated by a rule rather than chosen.

Common patterns, and they are documented by the sender rather than secret:

• Date of birth as DDMMYYYY or YYYYMMDD
• The last four or six digits of an account, card or identity number
• A customer or policy reference, sometimes with a fixed prefix
• Postcode with no space, sometimes lower case

If you are stuck, the sender's help pages state the rule. Find it once and you can use it for every statement they send you after that.

Doing this for a document you receive every month

If a bank or a payroll system sends you an encrypted PDF regularly, you have two sensible arrangements.

Unlock each one and file the plain copy. Easy to search, and the right choice if the folder itself is somewhere safe, like an encrypted drive or a computer only you use.

Keep them encrypted and unlock only when needed. Slower, and the right choice on a shared or backed-up-to-anywhere machine.

Avoid doing both: unlocking them and leaving both copies in a downloads folder. Then you get the hassle of the encrypted copy and the risk of the plain one.

After unlocking

Check two things. Both are easy to take for granted.

Does it still open correctly? Open the unlocked copy before deleting anything, especially if the original was made by an unusual system.

Is the content complete? Compare the page count with the original. It should be the same, because the pages are copied across. If it isn't, something went wrong, so keep the original.