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Passwords

How to change the password on a PDF

By DeckleUpdated

To change the password on a PDF, remove the old password with Unlock PDF, then add the new one with Password protect PDF. Enter the current password and choose Remove the password, then open the unlocked copy, type the new password twice and choose Protect this PDF. You need to know the current password, and your original file stays as it was throughout.

Unlock PDF

Three different privacy tasks

Password

Controls access

Metadata

Document properties

Redaction

Selected page content

Choose the change; inspect the saved copy

Conceptual comparison · access, properties and content require separate checks. No single task certifies complete privacy.

How to change a PDF password with Deckle

  1. Open Unlock PDF and choose the protected PDF, or drop it onto the page.
  2. Type the current password in Password and choose Remove the password.
  3. Download the copy with "(unlocked)" in its name.
  4. Open Password protect PDF and choose the unlocked copy.
  5. Type the new password in Password and again in Confirm password. It must be at least six characters.
  6. Choose Protect this PDF and download the copy with "(protected)" in its name.
  7. Open the new file and check that the new password opens it and the old one does not.

Each result screen confirms its half of the job: "Password removed" after the first step, "Password required to open" with "AES-256 protection added" after the second.

Why it takes two steps

Password protect PDF only accepts a file without a password, so a protected PDF has to be unlocked before it can be locked again. That keeps each step checkable: the unlock is tested to open without a password, and the new protection is tested to refuse an empty password and open with the new one.

Example: a shared board-pack.pdf was protected with a password a former colleague also knew. Unlock it with the old password to get board-pack (unlocked).pdf, protect that with a new passphrase, and you end up with board-pack (unlocked) (protected).pdf. Rename it to something clear before you send it, such as board-pack-2026-11.pdf.

Clean up the intermediate file

The unlocked copy opens for anyone who has it. Once the new protected file has passed its check:

  • delete the "(unlocked)" copy from your downloads folder, and
  • delete or archive the old protected file so the two versions are not confused.

Deckle never changes the files you choose. It does keep its own copy of each result in your browser's storage for this site until you close the document, so close the document in Deckle as well once you have downloaded the final file.

Make other changes while it is unlocked

The unlocked copy is the right moment for any other edits, because a protected PDF must be unlocked again before tools can change it.

Then protect the final version with the new password.

Choose the new password

Make it different from the old one in more than a digit, and longer than the six-character minimum. A passphrase of four unrelated words is easy to say over the phone and hard to guess. See how to choose a strong password for a PDF.

Tips

  • Store the new password first. Save it in your password manager before you send the file, because Deckle cannot recover it.
  • Tell recipients the password has changed. Send it by a different channel from the file; see how to share a password-protected PDF.
  • Check both passwords on the result. The old one should fail and the new one should open every page.
  • Keep signed originals. Unlocking and protecting rewrite the file, so a digital signature on the original will not validate on the new copy.

Other ways to change a PDF password

  • Preview on a Mac. Open the PDF with its current password, choose File > Edit Permissions, enter a new password under Require Password To Open Document, then click Apply. Preview changes the file you opened.
  • Adobe Acrobat Pro. Choose All tools > Protect a PDF, then Set security properties. On the Security tab, choose Change Settings and enter the new passwords. Acrobat asks for the permissions password if the file has one.

Frequently asked questions

Can I change a PDF password without knowing the old one?

No. The old password is needed to decrypt the file before a new password can be set. If you have lost it, see can you unlock a PDF without the password.

Does changing the password affect the content?

No. Pages, page sizes and text stay the same. The Producer property is set to Deckle in each copy.

Can I change the password on several PDFs at once?

No. Each file goes through both tools separately, one at a time.

Can I keep the same file name?

Deckle adds "(unlocked)" and "(protected)" so results never overwrite your files. Rename the final copy in your file manager.

Related tools

Sources