ImageToolKit

Blur Image Online — Apply Gaussian & Box Blur Free [2026]

Apply blur effects to images with adjustable radius. Choose between box blur and Gaussian blur. Perfect for backgrounds, privacy, and creative effects. Free browser-based tool.

Drop an image here or click to browse

Accepts JPEG, PNG, WebP, GIF, BMP

What is Image Blur Tool?

Image Blur Tool is a free online tool that applies blur effects to images. It supports both box blur (uniform averaging) and Gaussian blur (weighted averaging that produces a more natural result). Use it to create blurred backgrounds, obscure sensitive information in screenshots, or add artistic blur effects to photos.

How to Use Image Blur Tool

Upload an image by dragging it into the drop zone or clicking to browse. Select a blur type: "Box Blur" for a uniform averaging effect, or "Gaussian Blur" for a natural, smooth blur. Use the radius slider (1-20) to control the blur intensity — higher values produce a stronger blur. The preview updates in real time. Click "Download" to save the blurred image.

How Image Blur Tool Works

The tool loads your image onto an HTML5 Canvas and reads raw pixel data. For Box Blur, each pixel is replaced with the unweighted average of all pixels within the specified radius. For Gaussian Blur, a weighted average is used where closer pixels have more influence, producing a smoother, more natural result. The Gaussian kernel weights follow a bell curve distribution. Both methods process RGB channels independently. Everything runs in your browser.

Common Use Cases

  • Blur backgrounds in photos for a depth-of-field effect
  • Obscure sensitive information like faces, license plates, or text in screenshots
  • Create blurred background images for websites and presentations
  • Apply soft-focus effects to portraits and product photos
  • Generate blurred placeholder images for lazy-loading on websites

Frequently Asked Questions

What is the difference between box blur and Gaussian blur?▼

Box blur averages all pixels equally within the radius, producing a uniform blur that can look slightly blocky at high radii. Gaussian blur uses a weighted average where pixels closer to the center have more influence, creating a smoother, more natural-looking blur.

How do I choose the right blur radius?▼

Radius 1-3 produces a subtle softening effect. Radius 5-10 creates a noticeable blur suitable for background effects. Radius 15-20 produces a strong blur that can obscure details like text and faces.

Can I blur just part of an image?▼

This tool applies blur to the entire image. For selective blur, you would need to crop the area, blur it, and combine it back with the original.

Does this tool upload my images to a server?▼

No. All processing happens entirely in your browser using the HTML5 Canvas API. Your images never leave your device.

What image formats are supported?▼

You can upload JPEG, PNG, WebP, GIF, and BMP images. The blurred image is downloaded as a PNG file.

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