Redaction is not the same as drawing a black box over text in a PDF editor. If you simply add a black rectangle on top of sensitive text, the original text is still in the file — anyone can copy and paste it, or remove the rectangle.
True redaction permanently removes the underlying text data. Here's how to do it correctly.
The dangerous mistake most people make
A surprisingly common mistake is to add black shapes or use highlighting to 'hide' text in a PDF. The original text remains in the file and can be recovered trivially — by copying the page content, extracting text, or simply removing the overlay.
This has caused serious data breaches in government documents, legal filings, and medical records that were published with this false redaction.
How to properly redact a PDF online
- 1Go to the Redact PDF tool.
- 2Upload your PDF. The document is uploaded securely and processed on our server.
- 3Enter the text to redact. Type the specific words, names, or numbers you want to remove (e.g. 'John Smith, 07700 900123, ACC-4821'). You can enter multiple terms separated by commas.
- 4Click 'Redact PDF'. All instances of the specified text are permanently removed and replaced with black bars.
- 5Download and verify. Open the result and confirm the redactions look correct before sharing.
What types of information should be redacted?
- Personal identifiers: Full names, dates of birth, national ID numbers, social security numbers
- Contact details: Phone numbers, email addresses, home addresses
- Financial data: Bank account numbers, credit card numbers, IBAN codes
- Medical information: Diagnoses, patient numbers, prescription details
- Legal identifiers: Case numbers, witness names in certain filings
Redaction vs. password protection — which do you need?
These solve different problems. Redaction removes specific content permanently — even someone with full access to the file will not see the redacted information. Password protection controls who can open the file, but leaves all content intact for authorised viewers.
For sharing documents that contain sensitive data about third parties (clients, patients, employees), use redaction. For protecting your own private documents from unauthorised access, use password protection.
Frequently asked questions
QCan redacted text be recovered?
Not with our tool. The Redact PDF tool permanently removes the underlying text data from the PDF — it doesn't just add an overlay. The redacted content cannot be recovered through any standard means.
QDoes redaction work on scanned PDFs?
Scanned PDFs are images, not text — the redaction tool works on text-based PDFs. For scanned documents, use the OCR PDF tool first to convert the scanned image to searchable text, then apply redaction.
QHow do I redact a PDF on a Mac or iPhone?
Open Safari, go to pdftoolz.io/tools/redact-pdf, upload your file, enter the terms to redact, and download the result. No software installation needed on any device.