Real Gaussian softening
The blur is a true Gaussian convolution applied by the browser's canvas pipeline, so falloff is smooth and natural rather than a boxy smear.
Blur Image Online
Soften a photo or hide detail with an adjustable Gaussian blur slider.
- Upload
- Single file · 25 MB max
- Privacy
- Nothing is uploaded
- Cost
- Free · no sign-up · no watermark
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The tool is loading its code on your device. This happens once and is cached for later visits.
Processed entirely on your device
Your file is read, transformed and re-encoded inside this browser tab using JavaScript. There is no upload endpoint — nothing leaves your machine, nothing is stored, and the result is created as a local object URL that disappears when you close the page.
Overview
About the Blur Image Online
Add a smooth Gaussian blur to any image and control the radius from a whisper to a heavy wash. The slider previews live and nothing is uploaded.
What Gaussian blur does to pixels
A Gaussian blur replaces each pixel with a weighted average of its neighbours, where nearer neighbours count for more. The radius you set controls how wide that neighbourhood is: small radii soften edges subtly, large radii melt detail into smooth colour fields. The weighting curve is what keeps the result looking optical rather than smeared.
Choosing a radius for the job
Portraits and product shots usually want 1–4 px to take the digital edge off. Backgrounds behind text overlays benefit from 6–12 px so the type stays legible. Full obscuring of faces, number plates or confidential documents needs enough radius that no stroke remains distinguishable — verify at 100% zoom, not in a thumbnail.
Blur, detail and file size
Blurring destroys high-frequency detail irreversibly, so keep an unblurred original if you might want it back. On the plus side, smooth blurred regions encode compactly, which can shrink downstream file sizes when you later compress the image.
Local processing, full resolution
The effect is applied at the image's native pixel dimensions on an in-browser canvas, then saved as PNG. There is no downscaling trick and no server round-trip, so what you preview is exactly what you download.
Step by step
How to use the Blur Image Online
Drop an image onto the upload area or choose one from your device.
Move the blur-radius slider; the preview updates as you drag.
Stop at the softness you want — small values soften, large values obscure.
Download the blurred PNG at full original resolution.
Why use it
Benefits and common use cases
What this tool is good for, and what it deliberately does not try to do.
Live, reversible control
Because the slider re-renders from your untouched source each time, you can dial the radius up and down without cumulative quality loss.
Privacy-safe obscuring
Blurring faces, plates or confidential text happens on your device, so sensitive pixels are never transmitted anywhere before being obscured.
Questions
Frequently asked questions
Short, honest answers about quality, limits and privacy.
What blur radius should I use?
For gentle background softening, 2–6 px reads naturally. To make text or faces unreadable you usually need 15 px or more, depending on image resolution — preview at full size before downloading.
Does blurring reduce file size?
Often yes, because smooth gradients compress better than fine detail, but the PNG output is lossless so the saving is moderate. Use the image compressor for aggressive size cuts.
Can I blur only part of an image?
This tool blurs the whole frame. For regional blurring, blur the full image here, then composite, or crop the area first with the image resizer and blur that crop.