redact a PDF
Cover what has to go, and have it actually removed. The tool then reads its own output back and tells you what is gone.
There is no Google Drive or Dropbox button on purpose: those send the file through a server. Here is what happens instead.
in three steps
- Drop the PDF in, or choose it. Each page is drawn so you can see what you are covering.
- Drag across anything that has to go. Add a box with the button and move it with the arrow keys if you prefer.
- Redact, and read the check: the tool reopens its own result and lists the words that are no longer in it.
how it works
Drag across anything that has to go. Two boxes that touch become one, a drag too small to have been meant is ignored, and a box can be added with a button and then moved and resized with the arrow keys — dragging should not be the only way in.
When you redact, every page carrying a mark is drawn at twice its size, the marks are painted onto the drawing, and the page is replaced by that picture. Pages with no marks are copied as they are. That is the trade: the pages you redacted stop being searchable, and in exchange there is no text under the box to recover.
Then the tool reads its own work back. It reopens the file it just wrote, extracts the text of the pages it changed, and lists the words that were in the original and are not in the result. If your marks missed, it says so.
why a black rectangle is not redaction
A PDF is a stack of instructions, and a black rectangle is one more instruction drawn on top. The text underneath is untouched — still selectable, still copyable, still returned by every extractor there is. Governments, newspapers and law firms have all published documents redacted that way and had the covered names read out within the day.
There is a page here that shows it happening: drop a document with a black box over something and watch the text come out from under it.
why doing this locally matters here
Every tool on this site is better for running in your browser. This one would be self-contradicting otherwise. The reason to redact a document is that some of it must not be seen by the people you are sending it to — and uploading the unredacted original to a website in order to redact it gives the complete document to a party you had not even considered.
Here the original is opened by your own browser, the marked pages are redrawn in it, and the only file that leaves this tab is the one you save.
questions
Where does my PDF go?
Nowhere. The pages are drawn, marked and rewritten in this tab, and the check that reads the result back is run here too. Redaction is the tool where sending the file somewhere would be most absurd: the whole exercise is to stop other people seeing part of a document, and uploading it hands them all of it.
How is this different from drawing a black rectangle?
A rectangle drawn over a PDF is a shape sitting above the text. The words are still in the file: select them, copy them, or run any text extractor and they come out. Newspapers and law firms have published documents redacted that way and had the text recovered within hours. Here a page you mark is rewritten as an image of itself with the mark painted in, so there is no text layer left on it to recover.
What happens to the pages I did not mark?
They are copied untouched — same text, same images, same quality, still searchable. Only a page carrying a mark loses its text layer, because that is the only way to be certain the marked words are gone. It is a real trade and the tool makes it on the smallest number of pages it can.
How do I know it worked?
The tool checks its own output. After writing the file it opens the result, extracts the text of the pages it changed, and lists the words that were in the original and are not in the result. If your marks covered nothing, it says that too rather than letting you believe otherwise.
Can I redact a scanned document?
You can cover anything on it, and the page is rewritten the same way. A scan usually has no text layer to begin with — it is already a picture — so the black box is the whole of the removal, and it is a real removal: the pixels underneath are replaced, not hidden.
Is this really free?
Yes, with no account and no watermark. Advertising pays for the hosting. Since the document never reaches us there is nothing about it to sell, which matters more on this tool than on any other here.