How to blur part of a screenshot on a Mac

Short answer: macOS has no built-in blur tool. Preview and the Screenshot editor can cover something with a shape, but neither can blur it, so a real blur means a third-party app. And here is the part most guides skip: for anything sensitive you should not blur it at all, because a blur can be undone. This is the honest picture of your options, and when a blur is fine versus when you need something a blur cannot give you.

What macOS can and cannot do

Both Preview's Markup toolbar and the markup editor that opens after Cmd + Shift + 4 give you shapes, text, arrows and a highlighter. None of them include a blur or a pixelate. So the built-in move is not to blur, it is to cover: draw a rectangle, set the fill to solid at full opacity, place it over the area, and export a fresh file so the cover is flattened in. The Photos app has a Retouch tool that smudges a small region, but it is imprecise and was made for removing blemishes, not hiding information.

If you specifically want to soften a background or a face rather than cover it, that is where a third-party app with a real blur brush comes in. Just be clear with yourself about which job you are doing: softening for looks, or hiding something that matters.

Every way to hide a region, and whether it holds up

These are the common methods on a Mac, and how each one stands up if someone later tries to recover what was underneath.

The pattern is simple: a blur is a soft cover that keeps a trace of what was there, so it is fine for a face in a crowd and wrong for a password. If the region is text, a number or a small logo, cover it or scrub it instead. For the two most common cases there are dedicated walk-throughs: blurring text in a photo on a Mac and blurring a face in a photo on a Mac. For why a blur comes apart, see whether a blurred image can be reversed, and if you are just covering something for a share, censoring a screenshot covers the casual case.

The safe way, without the guesswork

Because the built-in options make you cover, flatten and then verify every time, I built ScrubShot to make the safe path the default. Press Fn + Space, it grabs the screen and opens an editor, and you drag over the region you want gone. The Scrub tool does not blur: it rewrites that region with a content-independent mosaic, each block filled from pixels sampled at random across the selection, so the cover has no relationship to what was underneath and reverses to nothing. It looks like a blur, but there is nothing left to recover, and it is baked into the image rather than sitting on a layer.

Crop, mark up, then Copy or Save. The whole flow runs on your Mac and makes no network connections, so the screenshot never leaves the machine. For the full method, including the manual Preview route done properly, see how to redact a screenshot on a Mac.

FAQ

Does Apple have a blur tool on Mac?

No. Neither Preview's Markup toolbar nor the Screenshot editor that appears after you take a shot has a blur or pixelate option. Both give you shapes, text and a highlighter, so the only built-in way to hide part of an image is to cover it with a filled rectangle. For an actual blur you need a third-party app, and the Photos app's Retouch tool can smudge a small area but was not built for this.

How do you blur out part of a screenshot on a Mac?

Since macOS has no blur tool, you either cover the area with a solid shape in Preview and export a fresh file, or you use a third-party app that offers a pixelate or blur brush. For sensitive information the solid cover is the better choice: a blur or pixelate over text can be reconstructed, so a soft blur that looks hidden may not be.

Is a blur safe for hiding sensitive information?

Not for text or numbers. A blur and a pixelation both keep a relationship to the pixels underneath, and tools like Depix and Bishop Fox's Unredacter recover the original characters from a pixelated patch, especially short structured text like codes and account numbers. A soft blur over a face in a background is usually fine; a blur over a password is not.

How do I blur an image on my Mac without installing an app?

You cannot truly blur one with the built-in tools, but you can hide the area, which is what most people actually want. Open the image in Preview, use the rectangle shape at solid fill and full opacity to cover the region, then export a new file so the cover is flattened in. That removes the information rather than smearing it.