How to redact a PDF properly

Redacted means sensitive information has been permanently removed or blacked out before a document is shared. To redact a PDF, mark the text with a redaction tool such as Redact PDF, apply it so the content underneath is deleted, then check you can no longer select or search the hidden words. A black box drawn on top is not redaction: the text is still there.

Redacting means permanently removing sensitive information, such as names, account numbers, addresses or medical details, before you share a document. The important word is permanently. Many "redacted" PDFs that end up in the news were only covered with black boxes, and the hidden text could be copied straight out from underneath.

Why a black box is not enough

A PDF stores text as real characters, not as a picture. If you draw a black rectangle over a sentence with a PDF editor, a highlighter tool or a comment, the text is still there underneath. Anyone can select it, copy and paste it, or search for it. The same is true if you change the text colour to black on black. True redaction deletes the content itself.

How to redact a PDF for free

1. Open the free Redact PDF tool. It works in your browser, so the document is never uploaded.
2. Choose your PDF and go to the page with the information to remove.
3. Drag a box over each part that must disappear: names, numbers, signatures, photos.
4. Check every page. Sensitive details often repeat in headers, footers and later pages.
5. Download the redacted copy. Pages with redactions are flattened into images with the black boxes burned in, so the hidden text no longer exists in the file.

Check your redaction worked

1. Open the redacted PDF and try to select the text under a black box. You should not be able to.
2. Use your PDF reader's search to look for a removed word or number. It should not be found.
3. Copy everything on the page and paste it into a text editor, to make sure nothing hidden comes through.

Do not forget the hidden places

• Document properties. A PDF can store the author's name, the company, and the original title in its metadata. Clear them with Edit PDF metadata.
• File names. "Smith divorce settlement.pdf" gives away what the redaction hid. Rename the file.
• Comments, form fields and attachments. These can hold extra text. Remove them in your editor, or flatten forms with Flatten PDF before redacting.
• Context. Removing a name is not enough if the job title, date and location still identify the person. Read the page as a stranger would.

Things to know about this method

Because redacted pages become images, the text on those pages can no longer be searched or copied. That is the point, but it also means the file may grow slightly. Pages without redactions stay as normal text. Always keep your original, unredacted file somewhere safe, because redaction cannot be undone.

When to get professional help

For legal discovery, court filings or freedom-of-information responses, there may be formal rules on what to redact and how to mark it, for example labelling each redaction with a reason code. Ask the court, regulator or your lawyer which rules apply. For legal document sets, you may also need Bates numbering so every page has a unique reference.

Frequently asked questions

What does redacted mean?

Redacted means sensitive information was permanently removed or blacked out before the document was shared or published, such as names, account numbers or addresses.

How do I redact a PDF for free?

Use a free redaction tool that removes the content rather than covering it. DocNova Redact PDF works in your browser, so the document is not uploaded.

How do I black out text in a PDF?

Mark the text with a redaction tool and apply it. Drawing a black rectangle or highlight on top only hides it from view; the text can still be copied.

Can a redacted PDF be unredacted?

Not if it was redacted properly, because the content is deleted. If someone only drew boxes over the text, it can be copied out from underneath, which is how many leaks happen.

Can I redact a PDF without Adobe Acrobat?

Yes. Browser-based redaction tools work on any device with no Acrobat licence. Always check the result by trying to select and search the hidden words.