Blur Image

What is Blur Image?

Gaussian blur softens an image by replacing every pixel with a weighted average of its neighbours, where weights follow a bell curve centred on that pixel. The wider the bell curve (the larger the radius), the further-out neighbours influence the result, and the more aggressive the blur. The output looks natural because the falloff is gradual, unlike a simple box blur which produces a flat, characterless smear. This tool applies a true Gaussian blur via Canvas filter, with a strength slider that maps to a radius between 0.5 and 30 pixels. At low settings it suggests soft focus, at mid settings it produces the bokeh-style background blur common in portrait photography, at high settings it fully obscures detail for redaction and privacy use cases.

Why use this tool?

Gaussian blur via Canvas filter is a single GPU-accelerated pass on modern browsers. Even a 4K image (3840x2160) blurs in well under a second. The strength slider provides live preview so you can tune the exact amount before downloading. The original file is never uploaded. The blurred image is generated locally in your browser, which makes the tool safe to use on screenshots that contain sensitive information you do not want sent to a third-party server.

Common use cases

The most common reason to blur an image is privacy. Screenshots of bank statements, employer emails, or apps containing names and dates often need to be shared publicly, blurring the sensitive parts is faster than redacting each piece of text manually. A blur radius of 15-25 pixels is usually enough to make text unrecoverable while leaving the surrounding context readable. Other workflows: creating a soft-focus aesthetic for blog headers, social media banner images, or website hero sections where the background needs to recede behind overlay text; faking shallow depth-of-field on a photo taken with a small-aperture camera (a portrait shot with a phone, say); softening a busy background in a product photo to make the foreground subject more prominent. For more selective blurring, where only part of the image needs to soften, use our Edit Image tool to brush blur onto specific areas.

How to use Blur Image

1. 1Drop your image into the upload area
2. 2Drag the blur strength slider to set the radius (1-30 pixels)
3. 3Watch the live preview update as you adjust
4. 4Download the blurred image in the same format as the original

Frequently asked questions

How much blur is enough to fully obscure text?

A Gaussian blur radius of about half the text height is usually enough to make text unrecoverable. For a screenshot where text is ~20px tall, set the radius to 10-12 pixels. If you need certainty for legal or personal-data redaction, use our Redact PDF tool, which removes the underlying data entirely instead of just visually obscuring it.

Can someone undo the blur and recover the original?

Gaussian blur is mathematically irreversible at any meaningful radius, because the operation discards spatial frequency information. There is no realistic way to recover the underlying pixels from a blurred image at radius 8+. That said, for true privacy in shared documents, a black redaction box is safer than blur because there is zero visual ambiguity.

Will blur reduce my file size?

Yes, often significantly. Blur removes high-frequency detail, which is what JPG and WebP compress least efficiently. A heavily blurred JPG can be 40-70% smaller than the original. PNG sees little change because lossless compression treats blurred pixels the same as sharp ones.

Can I blur only part of an image (faces, license plates)?

Not in this tool, the blur applies to the whole image. For selective blurring of faces, license plates or specific UI elements, use our Edit Image tool which lets you brush a blur effect onto chosen regions.

Does it support PNG transparency?

Yes. The alpha channel is blurred along with the color channels, which softens cutout edges slightly, this is usually what you want, since a blurred cutout sits more naturally against a new background.

Will the blur look natural or boxy?

Natural. The Canvas filter implements a true Gaussian distribution, which produces the smooth radial falloff seen in real out-of-focus photography. There is no banding or box-blur artefact even at the maximum strength setting.

1. 1For a sharp foreground against a soft background, first cut out the subject with Remove Background, blur the original, then layer the subject back on top. This is the standard fake-bokeh recipe.
2. 2If you are blurring a screenshot for privacy, take the screenshot at 2x or 3x the size you need first. Blur, then resize down (Resize Image). The blur survives the resize, but tells of the original underlying text fade further.
3. 3Light Gaussian blur (radius 1-2) before JPG compression often improves the result, since JPG handles smooth gradients better than noisy detail. The trick is invisible at the right radius and meaningfully shrinks the file.

How does it compare?

Phone editors usually expose a single blur strength that may go too far for redaction or not far enough for aesthetic soft focus. This tool gives full slider control and never uploads the source file, which matters when the image contains personal data.

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