How to redact a PDF for free

What a real redaction has to do

A black box is the visible part. The part that matters is underneath: after redaction, the hidden words must not be searchable, selectable or copyable, and there must be no separate box that someone can lift off. Plenty of published documents have leaked names and numbers because someone drew black rectangles over text that was still in the file. If a method only draws a box, it is not redaction, whatever the button says.

Redact a PDF in your browser with peadf

The redact PDF tool runs in your browser tab, so the unredacted document is never uploaded anywhere. That matters: sending a file to a server to remove secrets from it creates a copy of the secrets on someone else's computer.

1. 1

   Open the PDF

   Drop the file into the editor. It loads on your device.

2. 2

   Pick Redact and drag over each item

   Choose Redact in the toolbar and drag a box over every name, number or passage that has to go. Each box is black and marked for removal.

3. 3

   Search for repeats

   Press Ctrl+F (Cmd+F on a Mac) to find every other place the same name or number appears, on every page, and redact those too.

4. 4

   Export

   On export, each page with a redaction is rebuilt as an image from the original, without the content under the boxes. Editing is free; downloading needs a free account and starts at 99p for your first week.

The cost of doing it properly: a page that carries a redaction loses its selectable text entirely, not just under the box. Pages without redactions keep theirs.

Other free ways to redact a PDF

• Preview on a Mac: recent versions of macOS have a Redact tool under the Tools menu. Its behaviour has changed between releases, so test the result with the check below.
• Print to an image and back: printing the covered PDF and scanning it, or exporting each page as an image and turning the images back into a PDF with images to PDF, leaves nothing underneath. Every page loses its text, though, and the quality drops.
• LibreOffice Draw: the free office suite can open a PDF and has a redaction feature of its own. It is a desktop install and a heavier tool to learn for a one-off job.

What does not work: a black highlighter, a black rectangle from the comment or shape tools, or a white box. All of those sit on top of the page. Our guide on whether white out removes text from a PDF shows why.

Check your redaction before you send it

1. 1

   Search the exported file

   Open the redacted PDF and search for a word or number you removed. Nothing should be found.

2. 2

   Select all and paste

   Select all the text and paste it into a plain text editor. The redacted content must not be in it.

3. 3

   Try to move the black boxes

   Click each box. If any can be selected, moved or deleted, it is a cover, not a redaction.

Questions people ask