How to Redact a PDF in Preview on a Mac: Step-by-Step (2026)

To redact a PDF in Preview on a Mac, open the file, click the Markup button (the pen-tip icon in the toolbar), choose the Redact tool, drag over the text or image you want removed, then save. Preview warns you that redaction is permanent: once the file is saved, the content under the black box is deleted, not just covered. The Redact tool exists in macOS Big Sur (11) and later. On older versions, and if you use the Shapes tool to draw a black rectangle instead, the text stays in the file and anyone can copy it.

A rectangle from the Shapes tool only covers the text — Preview's Redact tool, and any true redaction, removes it.

Redact a PDF in Preview: the steps

Duplicate the file first. Preview redacts in place. Choose File → Duplicate (or copy the file in Finder) so you keep an untouched original.
Open the copy in Preview and click the Show Markup Toolbar button (the pen tip in a circle), or use View → Show Markup Toolbar.
Select the Redact tool. It is the icon with the black-barred text in the Markup toolbar, also reachable from Tools → Redact. The first time, Preview shows a notice that redacted content cannot be recovered after saving.
Mark what to remove. Drag across text to redact it, or draw a box over a region (a signature, a photo, a table cell). Repeat on every page, including headers, footers and page margins.
Save (Cmd+S). Saving applies the redaction and removes the underlying text and image data. There is no undo after this point, which is why step 1 matters.
Verify. Reopen the saved file, try to select text inside a black area, and press Cmd+F to search for a word you redacted. If nothing can be selected or found, the redaction is real.

macOS Catalina and earlier

Preview versions before Big Sur have no Redact tool. The common workaround (a black rectangle from Tools → Annotate → Rectangle) is not a redaction: the rectangle is an annotation layered over intact text. Either update macOS, or use a browser-based redactor as described below.

The mistake that leaks data

Even on a current Mac, people still reach for the Shapes tool because it is the first thing in the toolbar. A filled black rectangle looks identical to a redaction on screen. It is not: the recipient can select the text underneath, copy it, search it, or simply delete the shape in any PDF editor. Court filings, HR files and company disclosures have all leaked this way. The rule is simple: if the tool was not called Redact, the text is still there.

Where Preview's Redact tool falls short

Preview's tool does remove content, but it is a manual, one-page-at-a-time instrument. Expect these limits:

You have to find everything yourself. There is no search-and-redact and no automatic detection. On a 40-page contract with dozens of names, addresses and account numbers, the finding is the real work, and a missed item on page 31 is a leak.
Scanned PDFs have no text to find. Preview has no OCR. You can black out an area of a scanned page, but Cmd+F will not locate the names for you, so you are reading every page by eye.
Metadata and attachments stay. The Redact tool works on page content. Document properties, comments, bookmarks and embedded files are untouched, and they can carry the very names you removed.
No batch. Ten files means ten manual passes.
It rewrites the original. Forget to duplicate and the only copy of the document is the redacted one.

Redact a PDF on a Mac with automatic detection

For long, scanned, or numerous documents, use a redactor that finds the data for you and flattens the result. This runs in Safari or Chrome on macOS, with nothing to install:

Upload the PDF (or a JPG/PNG of a document) to Redact PDF AI. Scans are read with OCR first.
Choose the categories to remove: people, emails, phone numbers, addresses, organizations, dates, IBANs, card numbers. Add words that must always or never be redacted.
Review the proposed redactions in the Studio editor: keep, remove, or draw your own box over anything the AI missed.
Download the flattened PDF. Every page is rasterized and the text layer is dropped, so the output cannot be reversed by copy, search or forensic tools.

The AI scans every page, flags names, emails and account numbers, and redacts each match — you review before exporting.

Files are processed on EU and Swiss-hosted Azure infrastructure, deleted automatically, and never used to train AI models. The first document is free and needs no signup.

Preview vs an AI redactor on the Mac

| | Preview (Big Sur+) | Redact PDF AI | | --- | --- | --- | | Finds sensitive data | You do, by eye | Automatically, every page | | Scanned PDFs | No OCR | Built-in OCR, 100+ languages | | Output | Content removed, text layer kept elsewhere | Rasterized, no text layer | | Metadata and attachments | Untouched | Dropped | | Batch | No | Yes, plus an API | | Cost | Included in macOS | First document free, then plans |

Preview is the right tool for one short digital PDF with a couple of items to remove. Anything longer, scanned, or repeated is faster and safer with automatic detection.

Frequently asked questions

Does Preview on Mac really redact, or just hide text? On macOS Big Sur and later, the Redact tool in the Markup toolbar permanently removes the content once you save. A black rectangle from the Shapes tool only hides it and can be undone by anyone.

How do I check whether my Preview redaction worked? Reopen the saved PDF, try to select text inside the black box, and search (Cmd+F) for a redacted word. If either finds something, the content is still in the file.

Can Preview redact a scanned PDF? You can draw a redaction over any region of a scanned page and it will be removed, but Preview cannot search the scan for you. Use a tool with OCR if the document is long.

Why can I still copy the text under my black box? Because it was drawn with the Shapes or Annotate tool, not the Redact tool. Delete the shape, duplicate the original, and redo it with Tools → Redact, or use a redactor that flattens the page.

Is there a free way to redact a PDF on a Mac without Adobe Acrobat? Yes. Preview's Redact tool is free on Big Sur and later, and Redact PDF AI runs in the browser with the first document free and no signup.

What about redacting on an iPhone or iPad? The Markup tools on iOS have no Redact option. See how to redact a PDF on iPhone or iPad.

Related guides

How to redact a PDF: the full guide, including Adobe Acrobat and what to check before sharing.
How to unredact a PDF, and when you can't: the test for whether a redaction is real.
Redact PDF AI vs Adobe Acrobat