Image Blur Tool

What this tool does

The Image Blur Tool applies a variable-strength Gaussian blur to any image entirely inside your browser. A single slider controls the blur radius from 0 px (no blur, the image is unchanged) to 50 px (heavy blur). The canvas preview redraws in real time as you drag the slider — there is no button to press and no wait for a server. When you find the right amount, one click downloads the blurred result as a PNG.

The blur is implemented using the browser’s own canvas filter API, which delegates the computation to the GPU. Even on large images, the preview typically updates in well under a second. Edge bleeding — the hard border that normally appears when blurring near the canvas edge — is handled automatically by drawing the image with padding equal to twice the radius and then cropping back to the original size.

Why you might need it

Blur is one of the most versatile tools in image editing. Its most common applications fall into two categories: privacy and aesthetics.

For privacy, blurring allows you to obscure personal information in a screenshot — a name, an email address, a phone number, or a face — before sharing it publicly or attaching it to a bug report. The blurred region is visually obvious so reviewers know something is intentionally obscured, unlike a black rectangle which can look like a technical error.

For aesthetics, blur produces the soft-focus background effect that gives portrait photography its professional look. It is also used to create blurred background layers for design work — a photograph blurred to 20–30 px becomes an abstract colour field that works well behind overlaid text on a blog hero banner or a social media post.

Ecommerce sellers use background blur to draw the eye to a product without cropping or reshooting. Document owners blur confidential fields in scanned documents before sharing. Profile picture editors blur the background to simulate a camera lens effect.

How to use it

1. Drop your image onto the upload area, or click to browse.
2. The slider starts at 0 px — the image is displayed without any blur.
3. Drag the Blur radius slider to the right to increase the blur strength.
4. Watch the canvas update in real time at every slider step.
5. For fine control, click on the slider and use the arrow keys to nudge the value by 1 px at a time.
6. Click Download PNG to save the result.
7. Click Clear to load a new image and start over.

Format and quality notes

The output is always a PNG file. PNG is lossless, which means the smooth gradient tones that a Gaussian blur creates are captured faithfully without the banding or colour smearing that JPEG compression introduces. This matters especially at high blur radii where the entire image is made up of soft gradients — JPEG compression is notoriously poor at encoding such content.

If your eventual destination is a platform with a file-size limit, download the PNG from here and then run it through the Image Compressor to convert to WebP, which handles smooth-toned images well. JPEG is less suitable for blurred outputs than WebP for the same reason.

Tips for best results

For privacy blurring, a radius of 10–20 px is usually sufficient to make text unreadable while keeping the surrounding context recognisable. If the text is very small (a sub-heading or a label), go higher — 25–35 px.

For background blur on a portrait, use a separate image editor to select and mask the subject, then blur only the background layer. This tool blurs the entire image. If you want a quick depth-of-field simulation on an already- separated background layer, a radius of 15–25 px is typical for a shallow-focus look.

For abstract backgrounds — blurring a photo to use as a design backdrop — a radius of 30–50 px usually produces a pleasantly hazy colour wash that works well behind overlaid text. This technique is popular for social media header images and email campaign banners.

This tool works well alongside others in this canvas-filter family: apply a colour filter in the Image Filter Applier first, then blur the result here. Related tools include the Image Grayscale Converter for black-and-white blurred backgrounds, the Brightness & Contrast Adjuster for exposure correction, and the Pixelate & Mosaic tool for a sharp-edged pixelation effect instead of smooth blur.