How do I blur an image online?

Choose picture, drop an image on the stage or paste a screenshot. Leave Mode on Whole, set the radius and compare the original with the blurred preview. Wait for the preview to finish, then press Download. The blur is computed from the original pixels each time, so adjusting the radius does not repeatedly blur an already blurred copy.

How do I blur text, a face or only part of an image?

Switch Mode to Selection. Drag a box over the text or face, move the active box, or type Left, Top, Width and Height in whole source pixels. To blur several separate parts, press Keep this box, then move or redraw the active box over another area. Remove a kept box to exclude it. Every rectangle samples the original pixels, so overlapping areas are not repeatedly blurred. Pixels outside every box are copied unchanged by the blur step. JPEG compression can change them in the saved file; PNG avoids that compression.

Can I blur the background while keeping a person sharp?

There is no automatic background separation or freehand mask for a photograph. Whole mode blurs the person too; Selection mode blurs rectangular areas. This does not trace an irregular background around a person. For a webpage with separate background and foreground layers, Use blur on a webpage generates CSS that blurs a background image while leaving the foreground HTML content sharp.

What does the blur radius actually mean?

Radius is the standard deviation of the Gaussian, from 0 to 100 source pixels. At radius 12, the kernel reaches 36 pixels each way across 73 taps, truncated at three times the radius and normalised so its weights sum to one. Picture edges are repeated beyond the border. Radius 0 leaves every pixel unchanged. A larger photograph may need a larger radius for the same visible softness.

Can this make a blurry image clear again or securely censor text?

It adds blur; it does not remove blur, reconstruct missing detail or sharpen an image. Blurred text can remain readable or be partly recovered. For private details that must stay secret, use an image editor to replace them with an opaque solid shape. This tool supplies a visual effect rather than secure redaction.

Which image formats can I use and download?

Choose an image your browser can decode, such as PNG, JPEG, WebP, BMP or GIF. Output is a still PNG or JPEG; GIF animation is not preserved. PNG keeps the blurred alpha channel. The blur uses premultiplied colour to avoid pulling hidden colours out of transparent pixels. JPEG fills transparency with white and uses quality 0.92. Both outputs keep the original pixel dimensions.

Can I blur an image on iPhone, Android, Mac or Windows?

Use this page in a current browser on iPhone, Android, iPad, Mac, Windows or Chromebook. Choose a local picture, use touch to drag the selection or enter its dimensions, then download the result. Nothing needs installing. Image copying depends on browser clipboard support; Download remains available when image copying is refused.

Is my picture uploaded or remembered?

The image is decoded and blurred in this tab. No image bytes are uploaded or stored. Only valid radius, mode and format edits are remembered in browser storage; opening the page does not write settings. Preset pages have separate settings from the main page. If storage is blocked, the tool still works.

Is there a limit on image size?

There is no file-byte limit. Pictures can contain up to 30 megapixels, and the blurred area times the radius is capped at 360 megapixels times radius. A 30 megapixel photo can use radius 12; a 3 megapixel photo can use radius 100. Selection work is the sum of each rectangle’s area times radius, including overlaps that require separate processing. If a limit is exceeded, reduce the radius, remove a box or resize the picture.

Can I use it without a mouse?

The labelled radius field, slider and mode controls are keyboard accessible. Tab to the selection box and use arrow keys to move it; Shift with an arrow resizes it. Each press moves one screen pixel, or one source pixel when that is larger. The four labelled selection fields set its position and size directly, and errors explain invalid values.

How do I blur an image with CSS or on an HTML canvas?

Open Use blur on a webpage and choose image CSS, background CSS or canvas. Enter the image path you use on your website and adjust the radius above. Copy the generated HTML, CSS and script into your page. Image CSS blurs the whole image element. Background CSS uses a separate blurred layer so foreground HTML stays sharp. Canvas draws the decoded image with its browser’s blur filter. Browser filters may look different from this tool’s Gaussian export.

How do I show a blurred image while the original loads?

Choose your picture, use Whole mode and download a blurred PNG or JPEG. Host it at a placeholder image path and host the original at its own path. Open Use blur on a webpage, choose the loading-placeholder recipe and enter both paths. Copy the complete markup, styles and script to your page. It shows the blurred placeholder while loading, reveals the sharp image after a successful load, and handles cached originals too. A failed original leaves the placeholder visible. For a lighter placeholder, resize the blurred file first. This creates your own loading effect; it does not repair image delivery on someone else’s website.

Image Blur

Choose a picture, adjust the Gaussian blur radius and download a PNG or JPEG at the original width and height. Whole mode softens the entire image. Selection mode blurs rectangular areas over faces, text or other parts, keeping pixels outside every box unchanged before encoding. The core tool is free and needs no account.

originalnothing yet

The picture appears here.

blurrednothing yet

The blurred copy appears here.

or drop one on the stage, or paste a screenshot

Never uploadedNo accountBlurred in this tabFull resolution out

Radius
Mode
Size: no picture yet
Format

Radius is the standard deviation of the Gaussian, in pixels, from 0 to 100, over pictures up to 30 megapixels. Drag a box on the original to blur one part, or switch Mode to Whole.

Use blur on a webpage

Generate CSS, canvas or a loading placeholder for image paths you host yourself. These recipes use the radius above and blur a whole image. Browser CSS filters can differ from this tool's exported Gaussian.

Recipe Original image path Generated HTML, CSS and script

<img class="blurred-photo" src="/images/photo.jpg" width="800" height="600" alt="Describe your picture">
<style>
.blurred-photo { display: block; max-width: 100%; height: auto; filter: blur(12px); }
</style>

Whole imagea hard edge, 0 against 255, radius 1
becomes 77 against 178, with the step spread over 6 pixels
Dragged regionone rectangle, 4 by 4, radius 1.5
16 pixels blurred, the other 84 identical to the original
Radius 0no change
every byte of the original returned

Those three lines are printed by running the same code your picture goes through, not typed in by hand.

Your picture stays on this device. A separable Gaussian blur with weights that sum to one, computed on decoded pixels on this device. Radius 0 leaves the blur buffer unchanged; Selection mode writes only inside its rectangles. Canvas encoding can round transparent colours and JPEG adds compression. Output has no hidden original layer. Blurring is a visual effect, not a security control: text may remain readable or recoverable. Nothing is uploaded. There is no upload, no account and no watermark, and no image byte is handed to analytics either: the only thing the page records is that the tool was used.

Common questions

How do I blur an image online?: Choose picture, drop an image on the stage or paste a screenshot. Leave Mode on Whole, set the radius and compare the original with the blurred preview. Wait for the preview to finish, then press Download. The blur is computed from the original pixels each time, so adjusting the radius does not repeatedly blur an already blurred copy.
How do I blur text, a face or only part of an image?: Switch Mode to Selection. Drag a box over the text or face, move the active box, or type Left, Top, Width and Height in whole source pixels. To blur several separate parts, press Keep this box, then move or redraw the active box over another area. Remove a kept box to exclude it. Every rectangle samples the original pixels, so overlapping areas are not repeatedly blurred. Pixels outside every box are copied unchanged by the blur step. JPEG compression can change them in the saved file; PNG avoids that compression.
Can I blur the background while keeping a person sharp?: There is no automatic background separation or freehand mask for a photograph. Whole mode blurs the person too; Selection mode blurs rectangular areas. This does not trace an irregular background around a person. For a webpage with separate background and foreground layers, Use blur on a webpage generates CSS that blurs a background image while leaving the foreground HTML content sharp.
What does the blur radius actually mean?: Radius is the standard deviation of the Gaussian, from 0 to 100 source pixels. At radius 12, the kernel reaches 36 pixels each way across 73 taps, truncated at three times the radius and normalised so its weights sum to one. Picture edges are repeated beyond the border. Radius 0 leaves every pixel unchanged. A larger photograph may need a larger radius for the same visible softness.
Can this make a blurry image clear again or securely censor text?: It adds blur; it does not remove blur, reconstruct missing detail or sharpen an image. Blurred text can remain readable or be partly recovered. For private details that must stay secret, use an image editor to replace them with an opaque solid shape. This tool supplies a visual effect rather than secure redaction.
Which image formats can I use and download?: Choose an image your browser can decode, such as PNG, JPEG, WebP, BMP or GIF. Output is a still PNG or JPEG; GIF animation is not preserved. PNG keeps the blurred alpha channel. The blur uses premultiplied colour to avoid pulling hidden colours out of transparent pixels. JPEG fills transparency with white and uses quality 0.92. Both outputs keep the original pixel dimensions.
Can I blur an image on iPhone, Android, Mac or Windows?: Use this page in a current browser on iPhone, Android, iPad, Mac, Windows or Chromebook. Choose a local picture, use touch to drag the selection or enter its dimensions, then download the result. Nothing needs installing. Image copying depends on browser clipboard support; Download remains available when image copying is refused.
Is my picture uploaded or remembered?: The image is decoded and blurred in this tab. No image bytes are uploaded or stored. Only valid radius, mode and format edits are remembered in browser storage; opening the page does not write settings. Preset pages have separate settings from the main page. If storage is blocked, the tool still works.
Is there a limit on image size?: There is no file-byte limit. Pictures can contain up to 30 megapixels, and the blurred area times the radius is capped at 360 megapixels times radius. A 30 megapixel photo can use radius 12; a 3 megapixel photo can use radius 100. Selection work is the sum of each rectangle’s area times radius, including overlaps that require separate processing. If a limit is exceeded, reduce the radius, remove a box or resize the picture.
Can I use it without a mouse?: The labelled radius field, slider and mode controls are keyboard accessible. Tab to the selection box and use arrow keys to move it; Shift with an arrow resizes it. Each press moves one screen pixel, or one source pixel when that is larger. The four labelled selection fields set its position and size directly, and errors explain invalid values.
How do I blur an image with CSS or on an HTML canvas?: Open Use blur on a webpage and choose image CSS, background CSS or canvas. Enter the image path you use on your website and adjust the radius above. Copy the generated HTML, CSS and script into your page. Image CSS blurs the whole image element. Background CSS uses a separate blurred layer so foreground HTML stays sharp. Canvas draws the decoded image with its browser’s blur filter. Browser filters may look different from this tool’s Gaussian export.
How do I show a blurred image while the original loads?: Choose your picture, use Whole mode and download a blurred PNG or JPEG. Host it at a placeholder image path and host the original at its own path. Open Use blur on a webpage, choose the loading-placeholder recipe and enter both paths. Copy the complete markup, styles and script to your page. It shows the blurred placeholder while loading, reveals the sharp image after a successful load, and handles cached originals too. A failed original leaves the placeholder visible. For a lighter placeholder, resize the blurred file first. This creates your own loading effect; it does not repair image delivery on someone else’s website.

A separable Gaussian blur with weights that sum to one, computed on decoded pixels on this device. Radius 0 leaves the blur buffer unchanged; Selection mode writes only inside its rectangles. Canvas encoding can round transparent colours and JPEG adds compression. Output has no hidden original layer. Blurring is a visual effect, not a security control: text may remain readable or recoverable. Nothing is uploaded.