How to Pixelate an Image Online (Free, No Upload)

Go to pixeltools.io/blur, drop in your image, switch the effect tab from Blur to Pixelate, and drag the pixel-size slider (4–40px) until the area you want to hide is unreadable. Export as PNG, JPG, or WebP. Everything runs in your browser — the image is never uploaded to a server — so it's a fast option for redacting a screenshot, a face, or a document before you share it. There's no account to create and no watermark added to the download.

Pixelating (sometimes called a mosaic effect) breaks an area of an image into large, flat-colored blocks instead of smoothing it like a blur does. Each block takes on the average color of the pixels it covers, so fine detail — like the shape of a face, the characters in a password field, or the digits on a license plate — gets destroyed rather than just softened. The larger the block size, the less recoverable the original detail is. It's the classic "news broadcast" censoring look, and it reads instantly to viewers as "this part was intentionally hidden."

Open the [Blur tool](/blur) and upload your image (JPG, PNG, WebP, or HEIC all work). Click the Pixelate tab next to Blur — this switches the effect from Gaussian blur to a mosaic block effect. Use the pixel-size slider to control block size: 4px gives a fine, barely-there mosaic, while 40px is chunky and completely unreadable. Watch the live preview update as you drag. When it looks right, choose your export format and download or copy the result straight to your clipboard.

Both hide detail, but they do it differently. A Gaussian blur smooths pixels into their neighbors, which looks softer and is better for artistic effects like a blurred background. Pixelation replaces detail with hard, flat blocks, which is the stronger choice when the goal is genuinely obscuring information — a face, a license plate, an account number in a screenshot — because there's no gradient left to reconstruct. If you're redacting something sensitive rather than just softening it visually, pixelate at a larger block size.

Privacy: hide faces, license plates, or ID numbers before posting a photo publicly. Screenshots: cover account numbers, email addresses, or API keys before sharing a screen capture in a support ticket or tutorial. Content moderation: obscure graphic or sensitive regions of an image while keeping the rest visible. Spoilers: pixelate a plot-relevant image before revealing it online. Design: use the mosaic look as a deliberate retro or censored-media aesthetic in a graphic or thumbnail. In each case the goal is the same — make one region of the image unreadable while leaving the rest of the photo intact and usable.

For genuinely hiding something like a face or text, use a larger block size relative to the feature you're covering — as a rule of thumb, the block size should be large enough that no single block sits entirely inside one recognizable feature (like an eye or a letter). A 4–10px block on a small, low-resolution image can still leave enough structure visible to guess at the original; 20–40px is safer for anything you actually need to keep private. When in doubt, zoom into the preview after applying the effect and check whether you personally can still make out the detail.