Blur an Image Online

How it works

Choose your photos, set the strength with the slider and press Blur. The tool blurs the entire frame and scales the effect with the image resolution, so the same setting softens an 800-pixel screenshot and a 4000-pixel phone photo by the same visual amount. As a working example: a 3.5 MB photo blurred at strength 6 becomes a calm backdrop that headline text sits on comfortably, while strength 9-10 makes faces and short text impossible to pick out. Each result line shows the before-and-after file size — a blurred JPG usually shrinks noticeably, because fine detail is what costs the most space. A JPG source comes back as JPG; PNG and WEBP sources come back as PNG with transparency preserved, and you can process several photos in one batch.

This tool is also known as blur image online, blur a photo, make image blurry, photo blur tool, blur picture online free.

What is blur?

A blur computes each pixel's new value as the average of the pixels around it: the larger the averaged area (the radius), the more details bleed into each other and the softer the image becomes. This tool applies a box blur in separate horizontal and vertical passes, three times over; three box passes together approximate the Gaussian blur known from photography, which is why the result looks natural rather than blocky. The radius scales with the image's longer edge, so one strength setting produces the same visual softening on small and large photos alike.

What is pixelation (mosaic)?

Pixelation divides the image into large squares and paints each square a single colour — the mosaic look television uses to hide faces. It differs from blurring in texture: a mosaic produces hard-edged blocks and openly signals that something was censored, while a blur leaves a smooth, natural surface. A mosaic with small blocks can be partially reversed by pattern-matching techniques, so when the goal is hiding information, use either large blocks or a strong blur — and check the result yourself before publishing.

What is the difference between blurring and pixelating?

Both destroy detail, but they look different and serve different jobs. A blur smears pixels across a wide area; the result is smooth, and applied to a whole photo it gives an elegant background effect. Pixelation reduces the image to hard-edged blocks; the result deliberately looks censored and tells the viewer that something is hidden here. For aesthetics — cover images, backdrops — blurring is the right choice; to visibly mark a redacted area in a formal document, the mosaic is the more conventional signal. In both methods a low setting can be partially reversed, so when privacy matters, go strong.

A light blur is not enough for privacy

Blurring averages neighbouring pixels; the information is not destroyed, it is smeared over a wider area. At strengths 1-3 a short piece of text, a licence plate or a familiar face can still be recognised — and sharpening tools can partially bring it back.

If you genuinely need to hide something, push the strength to 8 or higher, then zoom into the downloaded file and check it yourself: ask not whether you can read it, but whether someone enlarging a screenshot could. Your source file is never modified and the output downloads as a separate file with a -bulanik suffix, so experimenting is safe.

Which strength for which job?

The right strength depends on what the blurred image is for. Trying a few settings takes seconds; these ranges are a starting point.

• Strength 1-3 → soft focus, a light depth-of-field feel; details stay recognisable
• Strength 4-6 → background or cover images that will carry a title or text overlay
• Strength 7-8 → making text in a screenshot unreadable before sharing it
• Strength 9-10 → rendering faces, plates and documents impossible to identify

Frequently asked questions

How do I blur a photo?

Choose the photo from the box, set the strength with the slider and press Blur. The converted file downloads with a -bulanik suffix, and you can process several photos at once.

Can I blur just a face or a licence plate?

This tool blurs the whole frame; there is no region selection. To hide a single area, crop the photo down to that area first with the crop tool and blur the crop, or use a high strength to make the whole image unreadable.

Is my photo uploaded to a server?

No. The blur runs entirely inside your browser; neither the file nor its name or content is sent anywhere. That is exactly why it is safe to use on sensitive images.

Can a blur be undone?

Not from the downloaded file — the sharp detail is simply not written into it. But note that light blurs leave rough shapes recognisable, so choose a high strength when hiding something. Your original file is untouched, so the sharp version stays with you.