Image Blur

This free online image blur tool applies a smooth Gaussian blur effect to photos in your browser — no upload required. Drag the radius slider to control how strong the blur is, hit Apply, and download the result. It is useful for softening backgrounds, creating a dreamy effect, or obscuring sensitive information across the whole image.

How to use

1. Drop a JPG, PNG, or WebP image into the upload zone.
2. Drag the Blur Radius slider (0–50 px) to set the blur intensity.
3. Click Apply to process the image.
4. Preview the blurred result and check the file size.
5. Click Download to save the blurred image.

Blur is not redaction — read this first

If you are hiding a name, an address, a card number, or a face because it must not be recoverable, blur is the wrong tool. A blur is a reversible mathematical operation: it spreads each pixel into its neighbours but does not discard the information, and deblurring techniques can recover legible text from a moderate blur. Pixelation has the same weakness — for a known font, the average colour of each block is often enough to reconstruct the original characters.

For anything that genuinely must not be readable, cover it with a solid opaque shape and re-export the image, so the pixels underneath no longer exist in the file. The PDF editor can lay a filled box over a region for document work. Then check the result: open the exported file and confirm nothing shows through, since a shape drawn in a layered editor and never flattened is no protection at all.

Blur remains the right choice for aesthetics — softening a busy background, creating a banner backdrop, reducing visual noise behind overlaid text, or suggesting privacy in a screenshot where the content is not actually sensitive.

Radius is in pixels, so image size matters

The blur radius is an absolute pixel distance, not a proportion of the image. A 10-pixel radius is heavy on a 400-pixel thumbnail and almost invisible on a 4,000-pixel photograph from a modern phone. If a blur looks far weaker than you expected, the image is probably much larger than it appears on screen — the browser is displaying it scaled down.

Two practical consequences. First, scale your radius with the image: roughly 1–2% of the width is a reasonable starting point for a visible effect. Second, if you plan to resize the image anyway, resize first and blur second — blurring then shrinking discards much of the effect you just applied.

Blur and file size

Blurring usually makes a JPEG or WebP smaller, because compression stores fine detail expensively and a blur removes it. PNG may not shrink as much, since it is lossless and optimised for flat colour rather than smooth gradients. If size is the goal rather than the effect, the image compressor will do it without changing how the picture looks.