To blur sensitive information in a screenshot on a Mac, you need either a workaround or an app, because macOS has no blur tool. The free way is Preview: draw a rectangle over the detail with the Markup tools, fill it with a solid color and save. That covers the text instead of blurring it, which is the safer choice for passwords and account numbers anyway. For real blur and pixelate, or to find private details automatically, use a screenshot editor such as Smooth Recorder.
What counts as sensitive in a screenshot
Screenshots pick up more than you meant to share. Before you send one, look for:
- Contact details: email addresses, phone numbers and names in a sidebar or a "To" field.
- Account and payment details: card numbers, order numbers, invoice amounts and balances.
- Secrets: API keys, tokens, passwords and anything in a config file or terminal.
- Network details: IP addresses, internal URLs and server names.
- Links: private document links, invite links and reset links, which often work for anyone who has them.
- Faces: people in a video call, a profile picture or a photo on the page.
- Background clutter: browser tabs, bookmarks, notifications and the menu bar.
Your options at a glance
| Method | Real blur or pixelate | Finds details for you | Cost |
|---|---|---|---|
| Preview and Markup: filled shape | No, covers with a solid box | No | Free, built in |
| Retake the screenshot | Nothing to hide | No | Free |
| Smooth Recorder | Yes, plus a black bar | Yes, Smart Redact | $19 once in early access |
The free way: cover it in Preview or Markup
Preview and Markup have arrows, shapes, text and highlights, but no blur or pixelate tool, in macOS 15 Sequoia, macOS 26 Tahoe or macOS 27 Golden Gate. A filled shape does the job.
- Open the screenshot in Preview. Or click the thumbnail that appears right after you take a screenshot, which opens the same Markup tools.
- If you don't see the tools, click Show Markup Toolbar.
- Click Shapes and choose the rectangle.
- Drag it over the email address, number or name you want to hide. Drag its handles to resize it.
- Click Fill Color and pick black, or a gray that matches the page. Set Border Color to the same color so there's no outline.
- Repeat for each detail, then choose File > Save, or File > Export to save a copy.
On a PNG or JPEG, the box becomes part of the picture once you save, and Apple's Preview guide notes that you can't move or delete annotations on an image after saving. That's what you want here: the text under the box is gone from the saved file.
Or just retake it
Often the quickest fix is to remove the detail before you capture. Close the extra tabs, switch to a test account, collapse the sidebar, or press ⇧⌘4 and drag over a smaller area that leaves the private part out. Nothing to hide means nothing to miss.
Why black bars are safer than light blur for text
Blur looks tidier than a black box, but for text it isn't always enough:
- Light blur can stay readable. Over large text, a soft blur leaves the shapes of the letters, and people can often make them out.
- Short values can be guessed. If the hidden text is a four-digit code or a known format like a card number, someone can try likely values, blur them the same way and compare.
- Coarse pixelation leaks shape. Big blocks over short text keep a rough outline of each word.
A solid bar removes the pixels entirely, so there's nothing to read or match. Use one for passwords, keys, tokens, account numbers and anything else that must stay secret. Blur and pixelate are fine for faces, background windows and details that are merely private, like a name in a sidebar. Whatever you use, zoom in to 100% and check it before you share.
Find and hide private details with Smart Redact
Covering details by hand works, but on a busy screenshot it's easy to miss one. Smooth Recorder's screenshot editor has Smart Redact, which looks for them for you.
- Press ⌥1, pick an area, a window or the screen, and press Return to take the screenshot.
- Click Edit on the card that appears to open the screenshot editor.
- Open the Redact tab on the rail. Smooth Recorder reads the screenshot on your Mac for private details. Nothing is uploaded.
- Under Kinds to Hide, tick what you want covered: email addresses, phone numbers, links, card numbers, keys and passwords, IP addresses, money amounts and faces.
- Under Cover with, choose Blur, Pixelate or Black bar, and set the Strength.
- Click Hide N details, where N is how many it found. Every one is covered at once.
Changed your mind? The button becomes Show N details, which takes the covers off again. If you switch the cover from Blur to Black bar while the details are hidden, the covers update in place, so you don't have to start over.
Adjust or add covers by hand
Each cover is an ordinary shape on the screenshot. Drag it to move it, pull its handles to resize it, or delete it if Smart Redact covered something you want to show.
For anything it didn't find, like a customer's name, a logo or a chart, use the Blur and Pixelate tools in the Annotate tab and drag over the area by hand. The same editor has arrows, text, numbered steps, crop and backgrounds, covered in how to annotate a screenshot on Mac.
Smooth Recorder is a native Mac app for macOS 15 Sequoia and later, $19 once during early access ($49 regular), with no subscription and no account (pricing). If you're comparing screenshot apps, see Smooth Recorder vs CleanShot X.
Tips for sharing screenshots safely
- Hide before you annotate. Cover private details first, then add arrows and text, so a label doesn't end up on top of something you meant to hide.
- Use black bars for secrets. Blur for faces and clutter, solid bars for passwords, keys and numbers.
- Check the edges. Browser tabs, notifications and the menu bar often hold names and email addresses.
- Watch long captures. A scrolling screenshot of a chat or an inbox can hold dozens of names. Scan the whole length.
- Rotate exposed secrets. If an API key or password was ever shared uncovered, change it. Covering it later doesn't help once it's been seen.
- Share the flat image. Send a PNG or JPEG, not a PDF or a project file where a box might sit on top of text that is still there.
- Think about what's next. If you're also recording a video, the same details show up there. How to record a bug report video covers preparing your screen.
Troubleshooting
The box in Preview has a colored outline. Set Border Color to the same color as the fill, or to none.
I can't move the box after saving. On an image file, saved annotations become part of the picture. Start from the original copy if you need to change them.
Smart Redact missed an email address. Text that's very small, blurred, low-contrast or partly cut off is hard to read. Zoom in on the source, take a sharper screenshot, or cover it by hand with Blur or Pixelate in Annotate.
Smart Redact covered something I need to show. Select that cover and delete it. Next time, untick its kind under Kinds to Hide before you click Hide.
The blur still looks readable. Raise the Strength, or switch the cover to Black bar.
I need the text, not the picture. To copy words out of a screenshot instead of hiding them, see how to copy text from your screen on Mac.