Why isn't a black rectangle enough to redact a PDF?

Because a drawn rectangle is just another object placed on top of the page. The original text is still in the file underneath it, so anyone can select it, copy and paste it, search for it, or simply delete the box in an editor. Real redaction removes the content itself, not just hides it.

How do I check whether a PDF was redacted correctly?

Open the redacted file and try three things: select and copy text across the black area and paste it into a notepad, use Ctrl+F / Cmd+F to search for a word that should be hidden, and run the file through a PDF-to-text converter. If none of them reveal the hidden words, the redaction worked.

Can I still search the rest of the document after redacting?

Pages you didn't mark stay exactly as they were, with selectable text. Pages that contained redactions are rebuilt as flat images, so their text is no longer selectable. If you need those pages searchable again, run the redacted PDF through OCR — it will read the visible text and skip the blacked-out areas.

Is it safe to redact sensitive documents with an online tool?

Only if the tool doesn't upload your file. The un-redacted original is the most sensitive version of the document. PDFAgent's Redact PDF runs entirely in your browser, so the original never leaves your device — only you ever handle it.

How to Redact a PDF Properly (Black Boxes That Can't Be Undone)

Drawing a black box over text is not redaction — the words are still there. Here's how to redact a PDF permanently, for free, in your browser, so names and numbers are truly gone. No upload.

Every few months a news story appears about a court filing, government report or company document where the “redacted” parts could be read by anyone with a mouse. The cause is almost always the same: someone drew black boxes over the text instead of actually removing it. The PDF looked censored, but the words were still in the file.

If you’re sharing a contract, a bank statement, a medical report, a payslip or a copy of an ID, this matters. Here’s how to redact a PDF properly — for free, in your browser, without uploading the original anywhere.

Covering vs. redacting: the difference that leaks data

A PDF page is made of layers of objects: text, images, vector shapes. When you use a highlighter or “draw rectangle” tool and set the fill to black, you add one more shape on top. The text underneath is untouched. That means anyone who receives the file can:

Select and copy the hidden text and paste it somewhere else.
Search for it with Ctrl+F (or Cmd+F) and see it highlighted under the box.
Delete or move the box in any PDF editor.
Extract all text with a converter and read everything, boxes or not.

True redaction does something else: it removes the content from the file so there is nothing left to recover. The black box is just the visible marker that something used to be there.

How to redact a PDF permanently (step by step)

Open the Redact PDF tool.
Select or drag in your PDF. A preview of the first page appears.
Drag a rectangle over each thing you want to hide: a name, an account number, a signature, a whole paragraph. Switch pages and mark as many areas as you need.
Leave “Also remove document metadata” ticked (it’s on by default) so the author name and title are cleared too.
Click Redact PDF and download the new file.

What happens behind the scenes: each page that has at least one marked area is rendered as an image, the marked areas are painted solid black, and the original page — with its text layer — is thrown away. The hidden content no longer exists in the output. Pages you didn’t touch stay exactly as they were.

Because all of this runs in your browser, the un-redacted original is never sent to a server. That’s the version you least want sitting on someone else’s computer.

What to redact (people usually forget some of these)

Before you start, go through the document with this list:

Personal identifiers: full names, ID/passport numbers, social security or tax numbers, dates of birth.
Contact details: home address, phone numbers, personal email.
Financial data: account numbers and IBANs, card numbers, balances, salary figures.
Signatures: a scanned signature can be copied and reused.
Headers and footers: reference numbers, file paths and names often hide here, repeated on every page.
Barcodes and QR codes: they can encode the same data you just blacked out in plain text.
Third-party information: other people’s names in emails, CC lists or tables.

Tip: search the PDF for each sensitive term (Ctrl+F) before redacting, so you find every occurrence — a name you hid on page 1 might appear again on page 7.

Don’t forget the hidden parts of a PDF

Visible text isn’t the only place information leaks from:

Metadata. PDFs store an author, title, subject and keywords. A document “anonymised” on the page can still say Author: Jane Smith in its properties. The redact tool clears this by default; you can also review or edit it with Edit PDF Metadata.
Form fields and annotations. Comments, sticky notes and filled form fields are separate layers. If the document has them, flatten the PDF first so everything becomes part of the page, then redact.
Previous versions. Some editors save changes incrementally, keeping older content inside the file. Redacting into a brand-new file (as this tool does) avoids that.

Check your work before sending

Never assume. Take two minutes to test the redacted file:

Copy test: drag-select across a blacked-out area, copy, and paste into a notepad. You should get nothing (on redacted pages, there’s no text layer at all).
Search test: press Ctrl+F and search for a name or number you removed. It should not be found.
Extraction test: run the file through PDF to Text. The hidden words must not appear in the output.
Properties test: open the document properties in your PDF viewer and confirm the author and title fields are empty.

If all four pass, the document is safe to share.

Common situations

Sending a bank statement to a landlord or lender. They usually need your name, the bank and the income lines — not every transaction. Black out unrelated payments and the full account number (keeping the last four digits is common practice).

Sharing a contract as an example. Redact the counterparty’s name, prices, signatures and addresses so the structure is visible without exposing the deal.

Submitting documents in a dispute or complaint. Hide third parties’ personal data that isn’t relevant to your case — in many countries data-protection rules expect this.

Posting a screenshot-style PDF publicly. Order numbers, emails and QR codes are easy to miss. Check headers, footers and small print.

After redacting: optional finishing steps

Need the text searchable again? Redacted pages become images. Run the file through OCR PDF to add a text layer back — it reads only what’s visible, so the blacked-out parts stay gone.
File too large? Image-based pages are heavier than text. Use Compress PDF before emailing.
Want to limit editing? Add a password with Protect PDF if the recipient shouldn’t modify the file.

Keep the original safe

Redaction creates a new file; your original is still on your device, un-redacted. Name the files clearly (for example statement_REDACTED.pdf) so you never send the wrong one, and store the original somewhere private.

Summary

A black box on top of text is a disguise, not a redaction. To redact a PDF properly you need a tool that removes the content underneath, clears the metadata and gives you a fresh file — then you verify it with a quick copy, search and extraction test. PDFAgent’s Redact PDF does all of that for free, right in your browser, without the sensitive original ever being uploaded.