How to Redact a PDF

Redacting a PDF for real

Some words in a document must not be seen by the next reader — a name, a phone number, an address, a salary, a medical detail. Covering them with a black box feels like enough, but it is not: in many PDFs the text is still there underneath the box, and anyone who copies the page can read it. Real redaction deletes the text itself, so there is nothing left to find. That is what this tool does.

You type the words or phrases to remove, one per line, and the tool finds them wherever they appear — matching anywhere inside a word, and ignoring case, so “Smith” finds “smith” and “Blacksmith”. The pages are then rebuilt as images with the text deleted, not covered. The page count and the page size stay the same, so the document keeps its shape, but the words you removed are gone. One file per run, up to 100 MB.

The honest limits are important, because redaction is a job where a mistake leaks. First, it only works on PDFs with a text layer: a scanned PDF cannot be searched, so nothing is found — OCR it first if the text has to be searchable. Second, because the pages are rebuilt as images, no text on a redacted page stays selectable or searchable — not just the words you removed. The whole page becomes a picture. The file also becomes larger, because images take more space than text. And third, redaction cannot be undone. Check the result before you share the file, and keep a copy of the original for yourself.

A few practical tips. List every form of a name or a number: a full name and a first name, a phone number with and without spaces, an address with and without the postcode. A word the tool does not find stays in the document, so check the result page by page — especially the pages you did not expect to contain the word. Redact a copy, never your only file. And remember that redaction removes text, not images: a name in a scanned signature or a photo of a document will not be found, because there is no text there to match.

It also helps to know what redaction does to the rest of the page. Because the pages are rebuilt as images, everything on a redacted page becomes a picture — the text you removed and the text you kept. That means the page cannot be searched afterwards, and the words you kept cannot be copied. If the document must stay searchable, redact a copy for sharing and keep the original for yourself. It also means the file grows: an image of a page takes more space than the text of a page, so a heavily redacted document can end up larger than the original. Check the size before you send it, especially if the file has to fit an upload limit.

One more honest note: redaction removes the words you list, and only those words. A name that appears as “J. Smith” will not be caught by listing “John Smith”, and a phone number written with spaces will not be caught by listing it without them. List every variation you can think of, and then read the result yourself, page by page, before you share it. The tool does the deleting; the checking is yours. A single missed word is a leak, and no tool can promise it found them all — which is why the final check, by a person, is part of the job, not an optional extra.

Everything runs in your browser. Your document is never uploaded to a server, so the private details you are removing stay on your device until you choose to share the file. There is no account, no daily limit, and no watermark. Open the tool, drop your PDF, type the words to remove, and check the result before you send it.

How to use this tool

1. 1Drop one PDF onto the Redact PDF page — up to 100 MB.
2. 2Type the words or phrases to remove, one per line.
3. 3Press Redact PDF and wait while the pages are rebuilt.
4. 4Download the result and open it.
5. 5Check every page before you share the file — redaction cannot be undone.