To redact a PDF for free, the words have to be taken out of the file, not covered. A black box drawn on top hides the words on screen and leaves them in the file, where anyone can copy them back out.
In September 2026 a United States federal court in New York ordered a lawyer to pay $2,316 after a white box marked “REDACTED” was placed over bank details in a court exhibit. The court found the details underneath could still be copied out or uncovered by moving the box, and they had already been shared online (Mercante v. Tarzia, Eastern District of New York, order of 18 September 2026).
The short answer. Open Redaction Studio, drop in the PDF file, mark what has to go and press Black out and check. It rebuilds each page as a picture, so no text is left underneath, and it checks its own result before giving you the file. It runs in your browser, so the document is not uploaded, and it is free to use there. Then check the new file a second time with Is It Really Blacked Out?
The steps
- Open Redaction Studio and drop in the PDF file. It is read in this browser tab only.
- Mark what has to go. Drag a box over a name or number, or use Find to mark every match of a word, plus ready-made patterns for email addresses, phone numbers, identity-style numbers, card-style numbers and dates.
- Choose a box style. Uniform blocks, the starting choice, makes every box the same width so the length of what was removed is not shown. Whole line covers the full line.
- Press Black out and check. Each page is rebuilt as a picture with the boxes painted in. The tool then opens its own result and checks it. If any check fails, it gives you no file.
- Check the new file again with Is It Really Blacked Out? A second, separate check is how professionals work.
What the free method costs you
Because the pages become pictures, the text in the new file cannot be selected or searched, and screen readers cannot read it. That is the price of leaving nothing underneath. Hidden details such as the author, comments and attachments are not carried over either, because the new file is built from scratch. Redaction Studio is free in the browser and costs $29 to own as a copy that works with the internet off.
If you used another program
Many programs only draw a box. Whatever you used, run the file through Is It Really Blacked Out? to see whether the words underneath can still be read, and through Remove metadata from a PDF file to see the author, comments and older versions the file may still carry. The guide What does redact mean in a PDF? explains the difference between covering and removing.
Questions people ask
Can I redact a PDF for free?
Yes. Redaction Studio is free to use in your browser. It removes the words by rebuilding each page as a picture, then checks its own result.
Does a black highlighter or black box redact a PDF?
No. Both put colour over the words and leave the words in the file, where they can be selected, copied or searched.
How do I check a redaction worked?
Run the new file through Is It Really Blacked Out?, which looks for words still readable under boxes and other leaks. You can also select all the text in the file, copy it and paste it into a plain text editor to see what comes out.
Will people know something was removed?
Yes. Redaction removes the words but shows that something was removed. Uniform blocks stop the box width from giving away the length of the word.
Before you go
Open Redaction Studio — free in the browser, nothing uploaded. Then check the result.