Redact PDF

When do you need to redact a PDF?

When you send a copy of your ID card to rent a flat, a bank statement to prove income, or a contract or certificate to someone who doesn't need everything in it. You want the other side to see the document, but not your full account number, your address, phone numbers, or transactions that are none of their business.

Why a black box isn't enough

The most common way people hide something is to draw a black rectangle over the text in Word or a PDF editor, and when we tested it, we recovered everything it covered. The number looks hidden, but the text is still in the file under the rectangle: anyone who selects the page and copies it, or opens the file in another program, can read it in full. This tool doesn't place a box over the text. It redraws the page as an image after filling the marked areas with black, so there's no character left underneath to extract.

Three ways to mark what to hide

• Draw: drag with the mouse or your finger over the area to cover. On a phone, turn on "Draw mode" to draw and turn it off to scroll between pages.
• Search: type a number or word, and every place it appears in the file is covered at once. A number written with spaces (such as 1234 5678) is found too.
• Auto-find: the tool looks for long numbers (bank accounts and cards), phone numbers, e-mail addresses and codes that look like ID numbers, and puts boxes on them. Review them and remove with × any you don't need hidden.

How to redact

1. 1
   Choose a PDF. Its pages appear below the upload box.
2. 2
   Mark what to hide by drawing, searching or auto-find. Each marked area shows in black with a red outline.
3. 3
   Press "Black out & create the file". After processing, the tool checks the result and shows you the check report.
4. 4
   Press "Preview result", look through the pages, then download. The file keeps its original name with _redacted added.

What exactly happens to the file?

• Pages with hidden areas are drawn as an image at 180 dpi, and the marked areas are filled with black before saving. These pages keep no selectable text, and nothing remains under the boxes.
• Other pages are copied as they are, with selectable, searchable text and filled-in form fields.
• Hidden data isn't carried into the new file: author name, title and creating program, comments and notes, links, attachments and the bookmarks panel.
• The check: after creating the file, the tool reads it back and confirms that the redacted pages contain no text and that the terms you searched for no longer appear on any page. If something remains on a page without a box, you get a warning with its page number.

Limits

• A scanned file or a photo of an ID card has no text, so search and auto-find can't work on it. Draw the boxes yourself; drawing works on any page.
• In Arabic text, search covers the whole text segment where the word was found, which can be longer than the word itself. If it covers more than you want, remove the box and draw a tighter one.
• Auto-find is a help, not a guarantee: it can miss a number written in an unusual way, and it can suggest a number that doesn't need hiding. Review the pages before creating the file.
• A password-protected or permission-restricted file has to be opened first with Unlock PDF.

Where does the processing happen?

Showing the pages, searching them, filling the areas and building the new file all happen in your browser. Your file and the text you search for aren't sent to any server, which matters especially for documents with ID and account numbers.

Frequently asked questions about redacting PDFs