Black box Safest
The pixels are replaced with solid black. Nothing of the original is left to recover. Use it for passwords, card and ID numbers, keys, and anything you’d regret.
Blur Screenshot
Hide names, emails, phone numbers and order IDs before you share a screenshot. Pick Blur, Pixelate or Black box and drag over what should go.
Low strength. Text under this region may still be readable, or partly recoverable. For passwords, card numbers and keys, use Black box.
How to blur a screenshot
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1
Add the screenshot
Press Ctrl V to paste one you just took, drop the file on the box, or tap the box to choose it. PNG, JPG, WebP, GIF and BMP all open.
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2
Drag over what to hide
Pick Blur, Pixelate or Black box, set the strength, and drag a rectangle. Add as many as you need. Click a region to change its mode or delete it, and Ctrl Z takes back a step.
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3
Download or copy
Download PNG saves the full-size image with the changes written into the pixels. Copy image puts it on the clipboard, ready to paste into a chat or an email.
What to hide before you share
The things people forget are usually not in the middle of the screenshot. They’re in the corners, the tab bar and the chat header.
Email addresses
Yours, and everyone in the To and CC lines of an email you’re showing.
Phone numbers
Including the ones in email signatures and at the top of a chat window.
Home and delivery addresses
On orders, shipping labels, invoices and map screenshots.
Order IDs and tracking numbers
With an order number, someone can contact support and pretend to be you.
Bank cards and account numbers
Cover the whole number, not just the middle digits. Same for IBANs and payment QR codes.
API keys and tokens
Anything that looks like
sk-…,ghp_…or a long random string. If one was already shared, change the key anyway.Avatars and faces
A profile photo identifies someone faster than their name does.
The other person’s name in a chat
They didn’t agree to be in your screenshot. Their avatar and the group name too.
Blur vs pixelate vs black box: which is safer
All three are written into the pixels of the PNG you download. The file has no layers that someone could switch off. What differs is how much of the original survives.
Pixelate Fine when coarse
Each block becomes the average color of its pixels. Big blocks are safe for most things. Small blocks over short text in a known format, such as a card number, have been rebuilt before by trying candidates until the pixelation matched.
Blur Weak blur can be undone
Blur looks the softest, which is why people like it for faces and backgrounds. A light blur can often still be read, or partly sharpened back. Here, stronger settings first shrink the area to a few pixels before blurring, so most of the detail is gone from the file.
Below strength 4 the tool warns you. Writing a new PNG also means nothing from the original file comes along. That matters: in 2023, phone and desktop screenshot editors were found to leave the cropped-out part inside the saved file (the bug was nicknamed aCropalypse).
Windows
Blur screenshots on Windows while you capture
If you share screenshots every day, doing it afterwards in a browser gets old. The OldSnap desktop app redacts while you capture.
Press Ctrl 1, select the area, press B. It looks for email addresses, phone numbers, Chinese ID numbers, bank card numbers, IP addresses, links, faces and QR codes, and puts a separate mosaic over each one. All of it runs offline, nothing is uploaded.
It finds things by their format, so it misses names, street addresses and numbers written in unusual ways. Phone numbers are matched in Chinese formats and international ones that start with +. Look before you send. One undo removes everything it added, and each mosaic can be moved or deleted.
Free. Windows 10 / 11, 64-bit, no admin rights needed.
FAQ
Is it free?
Yes. There’s no sign-up, no watermark and no limit on how many images you blur. It runs in your browser, so a use costs me nothing and there’s nothing to meter.
Is my image uploaded?
No. The image is opened and edited with canvas inside this tab, and the server never receives it. The only request this page makes on its own is a click count when someone presses the Download OldSnap button, and that carries no image and nothing personal. You can watch the Network tab in your browser’s developer tools to check.
Can blurred text be recovered?
Black box can’t be: those pixels are replaced with solid black. Strong blur and strong pixelation here throw away most of the detail before the PNG is written. Weak settings are a different story. Text under a light blur or small pixel blocks can sometimes be read or rebuilt, especially a short number in a known format. For passwords, card numbers and keys, use Black box.
Does it work on phone?
Yes. Tap the box to pick a screenshot from your photos, then drag with one finger to draw a region. Download saves the PNG. Copying an image to the clipboard works in recent Chrome, Edge and Safari. If your browser can’t do it, the page tells you and you can download instead.
Which formats?
Anything your browser can open: PNG, JPG, WebP, GIF (the first frame) and BMP, and AVIF in most current browsers. The result is always a PNG at the original size. Images over about 36 megapixels are refused, because browsers can’t hold them in a canvas reliably.