Image Blur Radius 🌫️

About the Image Blur Radius tool

The Image Blur Radius tool runs entirely in your browser. Drop or select an image, set the Blur radius slider from 1 to 30 pixels, and click Apply. The tool implements a true separable Gaussian blur: a 1D Gaussian kernel of size 2·radius + 1 is generated with σ = radius / 2, then convolved horizontally and vertically in two passes. This produces the same result as a full 2D convolution at a fraction of the cost — O(w·h·r) instead of O(w·h·r²). The kernel weights follow G(x) = exp(−x² / (2σ²)) and are normalized to sum to 1. Nothing is uploaded; all processing is local.

How to use it

1. Click the drop zone or drop an image file onto it.
2. Drag the Blur radius slider — larger values produce a stronger blur.
3. Click Apply to render the blur onto the image.
4. Click Download to save, Reset to restore, or Clear to start over.

Frequently asked questions

What blur algorithm is used? A separable Gaussian blur with two 1D convolution passes (horizontal then vertical). The kernel size is 2·radius + 1 and σ scales with the radius.

What is the output format? The download is a PNG file, preserving detail without compression artifacts.

Does this tool upload my images? No. All processing happens locally in your browser. Your image never leaves your device.

Can I apply the blur multiple times? Yes. Each Apply works on the current canvas, so successive clicks compound the blur. Use Reset to return to the original.