First, the conflict of interest. We make Zero-Trust PDF Studio, the tool on this site, so this comparison is written by one of the things being compared. We are not affiliated with, sponsored by or endorsed by any other company named here, and their product names belong to them. Every statement about another tool comes from that tool’s own website as we read it on November 6, 2026. Each row links to its main source and names any other page it used, so you can see whether it is still true.
What is the best free PDF redaction tool?
There is no single best one, but every good one passes the same test: it takes the text out of the file rather than covering it, and it lets you check that it did. Beyond that, choose by where the document is allowed to go. A browser or desktop tool keeps it on your machine, and several tools, upload and local alike, add OCR for scanned pages.
The rest of this page is about those two questions, in that order, because the second one only matters once the first has been answered. A tool that never uploads your file and leaves the text sitting under a black rectangle has protected nothing.
Removed or covered
A black box drawn on top of a sentence hides it from the eye and leaves it in the file. Select the area, copy, paste into a text editor, and the words come back. That is not a hypothetical. In January 2019, a filing by Paul Manafort’s lawyers in federal court carried black bars over passages that anyone could copy out, anda column in the ABA’s Judges’ Journal walks through what the bars were hiding and how reporters found it.The docketshows the redacted response as entry 471 and a corrected version as entry 472, both dated January 8, 2019. The NSA had published guidance on the same failure fourteen years earlier,Redacting with Confidence, written for reports converted from Word to PDF.
Every tool in the table below says its redaction is permanent. Fewer say how, and the method matters. Rasterizing turns the page into a picture with the bar already part of it, which is blunt and easy to verify: there is no text left on that page to find. Removing only the characters under the bar keeps the rest of the page searchable, and leaves a subtler trail. Researchers have shown that the sub-pixel spacing of the characters around a redaction can be enough to recover a redacted name, even when the redacted characters themselves are gone (Bland, Iyer and Levchenko, 2022). Rasterizing a page throws away the text layer those exact positions are stored in, leaving only pixels. It does not hide how wide a bar is, which says roughly how long the removed text was, and none of the methods on this page hides that.
Uploaded or kept on your device
An upload tool sends your PDF to the company’s servers, redacts it there and sends the result back. For a while the document exists on a computer you do not control, under that company’s retention policy; the upload tools below all publish one, deleting files after an hour or two, once the result has been downloaded, or when the session ends. For plenty of documents that is fine. Some documents, and some employers, rule it out.
A browser tool does the work inside the tab. The code arrives from the website, but the document is read from your disk and stays there, which you can confirm in about a minute with the browser’s own network panel, or by switching off Wi-Fi once the page has loaded and seeing whether it still works. Desktop programs make the same promise with an installer instead of a web page; PDF24, for one, also offers a free offline Windows program alongside its upload tool. In every case you are still trusting someone’s code. You are just not handing them a copy of the file.
The tools, by their own descriptions
Read on November 6, 2026, from each tool’s own pages. Where a row says “according to,” we are reporting the company’s claim and did not test it ourselves. We started from a list of well-known upload tools, smaller in-browser ones and one Windows program, and kept those whose own pages say where a file is processed. One widely used tool was left out because its redaction page says both that files are processed in the browser and that they are processed on its servers. No row comments on anyone’s security. Prices and limits change, so the link in each row is the thing to trust over this table.
| Tool | Where the file is processed | Free tier | How it redacts |
|---|---|---|---|
| Zero-Trust PDF Studio (this site) | In the browser. The file is never uploaded, and the tool works with the network switched off once loaded. | No limit, no account, no watermark. | Rasterizes each marked page and rebuilds the file without it. Find takes words, a pasted list of terms, or checked patterns for Social Security, card, routing and account numbers. Reads the export back and checks it. |
| PDF24 ToolsSource: PDF24 redaction page | Uploaded to servers in Germany and deleted after one hour, according to PDF24. | No limits and no registration. | Black boxes, with the pages that carry them rasterized when the file is saved. Search with an option to redact every match. |
| iLovePDFSource: iLovePDF security pageAlso: ilovepdf.com/redact-pdf | Uploaded. Its security page says files are deleted within two hours of being processed. | A daily limit is not stated on the redaction page. | Its redaction page says it permanently removes visible text and graphics and finds card numbers, phone numbers and email addresses; a Smart redact option adds names, Social Security and other ID numbers, account numbers and addresses. |
| RedactPDF.ioSource: RedactPDF.ioAlso: redactpdf.io/pricing | Encrypted in the browser, then processed on servers in the EU and deleted after download, according to the company. | Five documents a month, up to 25 pages and 5 MB each, per its pricing page. | Detects personal data automatically for review, then removes the visible text and the text layer. Includes OCR. |
| PDF4meSource: PDF4me redaction page | Uploaded over HTTPS, processed on its servers and removed automatically once the redaction is finished, according to PDF4me. | Free to start with no account. The free limits are not stated on the page; paid plans raise them. | Black out text, images and any area you draw over. PDF4me says the content underneath is deleted from the file. |
| DocuflairSource: Docuflair redaction page | Uploaded to servers in Germany or Austria and deleted when the session ends, according to Docuflair. Its page asks people not to put real client, citizen or patient data into the free version, and points to its on-premises product for that. | No sign-up. Files up to 20 MB, in PDF, Word, Excel, PowerPoint or image formats. | Runs OCR, detects nine kinds of personal data plus your own words and regex patterns, and removes the underlying text, according to Docuflair. |
| XodoSource: Xodo tool privacy tableAlso: xodo.com/redact-pdf | In the browser, according to Xodo’s tool privacy table. | One redaction a day without registering. | Text, whole pages, and presets for email addresses, card numbers and phone numbers. |
| PrivacyScrubberSource: PrivacyScrubber | In the browser, according to PrivacyScrubber. | PDFs of up to five pages. | Its blackout mode turns pages into images with the bars burned in. Detects card numbers, email addresses and phone numbers. |
| Tools360Source: Tools360 redaction page | In the browser, according to Tools360, which says no files are uploaded to its servers. | Files up to 50 MB, no account. | Draw boxes. The page says text, vector paths and image pixels under each box are removed. |
| DumPDFSource: DumPDF redaction page | In the browser, according to DumPDF. | Free, no account. | Drag boxes over text or images. Its Flatten option converts each page to an image, which it says makes the original text unrecoverable. |
| hddnSource: hddnAlso: hddn.app/pricing | In the browser, according to hddn, which says there is no processing server and that it keeps working offline once loaded. | A monthly allowance of exports with no account, for PDFs up to 10 MB. Paid plans raise both. | Removes the covered content from the PDF rather than drawing over it, and offers an image-only PDF when a file cannot be exported safely that way. Detects names, email addresses, IDs, account numbers and dates. |
| RedAction PDF ToolSource: RedAction PDF Tool pageAlso: its Microsoft Store listing | On your computer: it is a Windows program, and Beartalk, which makes it, says files are not uploaded for processing. | Three PDF redactions free, then a one-time purchase through the Microsoft Store. | Detects names, email addresses, phone numbers, addresses and ID numbers for review, with OCR for scanned pages. Beartalk says selected content is permanently removed. |
Where this site comes out behind
Rasterizing is our method, and it has the cost described above. A page you mark loses its text layer completely, so every word on it, not only the words under the bars, stops being selectable and searchable, and a screen reader can no longer read any of it. Pages you do not mark keep their text exactly as it was. If the rest of a redacted page has to stay searchable, look for a tool that says it removes only the characters under the bar, and test it as described below. The paid desktop route is covered on redacting without Adobe, including what Acrobat does better.
There is no OCR here, so Find cannot see a scanned page; those pages have to be marked by eye, and the tool names them. Several tools above run OCR first, including some that keep the file on your device. And because everything happens on your device, a very large scan is slow, and on a phone it can run the browser out of memory.
How to test any of them yourself
You do not have to trust this table, or us. Make a test document with a made-up number in it, redact the number with whichever tool you are considering, open the exported file, select everything and paste it into a text editor. If the number is there, the tool covered it. The checker on this site does a more thorough version of the same test on any PDF, including one redacted somewhere else, without uploading it.
For where the file goes, open your browser’s developer tools before you add the document, switch to the Network panel and watch for a request about the size of your PDF. Or load the page, switch off Wi-Fi, and see whether the tool still works. How to run both checks against this site, and what each of them cannot show, is oncheck these claims.