How to blur part of a screenshot on a Mac

Does a Mac have a built-in blur tool for screenshots?

No. As of macOS 27, none of the apps a screenshot passes through can blur or pixelate part of an image. Apple's own Preview guide lists every Markup tool for images: the rectangular, elliptical and lasso selections, Smart Lasso, Instant Alpha, Sketch, Draw, Shapes, Text, Sign, Adjust Color, Adjust Size, the shape and text style controls, rotate and crop. There is a Highlight and a Zoom lens among the shapes, but nothing that frosts or mosaics a region.

That leaves three routes, and which one fits depends on what you are hiding and where the screenshot is going:

• Cover it with an opaque shape using Markup. Built in, and the safest option for text.
• Pixelate a face with Photos Clean Up, if your Mac supports Apple Intelligence. Faces only, and only in Photos.
• Use a free blur or redact tool outside the built-in apps, when you want the softer look of a real blur.

And if the screenshot is of a web page, there is a fourth route that skips editing entirely, covered in the last section.

Cover sensitive data straight from the screenshot thumbnail

The quickest built-in method happens before the file is even saved. When you take a screenshot, macOS shows a floating thumbnail in the bottom-right corner for a few seconds, and clicking it opens a Markup window.

1. Press Shift Command 4 and drag over the area you want (or Shift Command 5 for the full Screenshot toolbar).
2. Click the floating thumbnail before it slides away.
3. Click the Shapes button and choose the rectangle. Drag it over the name, email or number you want gone.
4. Set Fill Color to a solid color (black is the convention) and make sure the border and fill are fully opaque. An unfilled rectangle is only an outline.
5. Click Done. The screenshot saves as a PNG with the box in it.

If the thumbnail does not appear, it may have been turned off: press Shift Command 5, open Options, and enable Show Floating Thumbnail.

Cover sensitive data in Preview

For a screenshot that is already on disk, Preview gives you the same tools with more room to work.

1. Open the screenshot in Preview.
2. Click the Show Markup Toolbar button if the toolbar is hidden.
3. Click Shapes, pick the rectangle, and drag it over the sensitive area. Use the blue handles to resize it so it covers the text with a margin to spare.
4. Set Fill Color to black or any solid color.
5. Repeat for every field, then File, Export, and save a PNG or JPEG copy to send.

PNG and JPEG files hold only pixels, with no annotation layer, so in the exported file the box simply replaces what was underneath. Exporting a copy is better than saving over the original for a second reason: Preview keeps earlier versions of an edited file on your Mac under File, Revert To, Browse All Versions. That is a useful undo for you and the reason to share the exported copy rather than the file you have been editing.

The PDF trap: shapes on a PDF can be removed

If the screenshot ended up inside a PDF, a black rectangle is not a redaction. In PDFs, Preview's shapes are annotations sitting on top of the page, and Apple's guide says that File, Save and File, Export keep annotations editable. Anyone with a PDF editor can select the box and delete it, and the text is still there underneath.

Two built-in ways to make it stick:

• Redact Selection for text in a PDF. Apple notes you can change a redaction while editing, and it becomes permanent once you close the document. Work on a duplicate.
• Flatten with File, Print, then Save as PDF, which Apple describes as making annotations permanent so they cannot be edited.

The wider version of this lesson, including the layered-file and cropped-image traps in other apps, is in how to redact a screenshot.

Photos: Clean Up pixelates faces, Markup covers the rest

The Photos app gets closer to a blur than anything else on the Mac, for faces only. Clean Up, the Apple Intelligence tool for removing distractions, treats faces specially: Apple's guide says that if you brush over a person's face, it may become blurred with a pixelated effect.

1. Import the screenshot or photo into Photos and double-click it.
2. Click Edit, then Tools, then Clean Up.
3. Brush over the face. Click Done when it looks right.
4. Export a copy (File, Export) to share.

Clean Up needs a Mac with M1 or later, macOS Sequoia 15.1 or later, and Apple Intelligence available in your language and region. It is aimed at faces, not at text, so it will not frost an email address or an account number. And Photos keeps the original of every edit so you can choose Image, Revert to Original, which is why the exported copy is the thing to send.

For text in Photos, the Markup extension (Edit, then Extensions, then Markup) offers the same filled shapes as Preview.

When you need a real blur or pixelation

A black box is the right call for passwords, keys and account numbers. It is not always the right look: a product screenshot for a blog post or a support article reads better with a soft blur than with black bars. For an image you already have, the free Blurr.ing redact tool does it in the browser: drop the screenshot in, drag over each area, choose a solid box, a blur or a pixelation, and download the result. The image is processed on your Mac inside the browser tab and is never uploaded.

Which of the three to pick comes down to what you are hiding:

Swipe sideways to see every column.

For web pages, blur before you capture

Most screenshots on a work Mac are of a web page: a dashboard, an inbox, an admin panel, a bug in a staging app. For those, editing afterward is the slow path. Every screenshot needs its own round of boxes, and it is easy to miss a field.

Blurr.ing moves the redaction into the page. Open it in Chrome, Edge, Brave or Arc, then draw a box over a region, click an element, or select a run of text, and it frosts in place. Now take the screenshot with Shift Command 4 or any other tool: the image contains only blurred pixels, with no original data under them and nothing to fix in Preview. Manual blurs are free and unlimited, with no account.

The extension also has its own capture: press Cmd Shift S, select an area, and the shot arrives with the page's blurs already in it, plus a card to blur more areas on the image, add a background, padding and rounded corners, and copy or save it. The image is built in your browser and never uploaded. The free plan includes 5 captures; the rest of the walkthrough is in blur screenshots before you take them.

The extension works on web pages only. For a screenshot of a native Mac app, use the Markup box or the redact tool above.