How to blur the background of a photo
Upload an image and the tool opens with the Blur option selected. The server identifies the main subject and keeps it sharp, then applies a Gaussian blur to the rest of the original photo and places the subject back on top. Use the Blur strength slider, from 2 to 40, to go from a slight softening to a heavily blurred backdrop, then download as JPG, PNG or WebP.
Strength scales with the image width, so a large photo gets the same look as the preview rather than a weaker blur. The output keeps the original dimensions.
Why blur a background
A blurred background removes distractions such as clutter, signs or other people, and draws the eye to the subject. It also mimics the shallow depth of field of a wide-aperture lens, which makes phone photos look more like they were taken with a dedicated camera.
Values around 8 to 15 give a natural portrait look for most photos. Higher values create a dreamy, abstract backdrop. Very low values are useful when you only want to tone down a busy pattern without making the edit obvious.
Limits of a digital portrait effect
A real lens blurs objects more the further they are from the focal point, and keeps the ground near the subject's feet relatively sharp. This tool blurs the whole background evenly, so in full-body shots the floor right next to someone can look a little unnatural. Head-and-shoulders portraits and product shots hide this best.
Around the edges, especially hair, the blur may leave a faint sharp halo or soften a few strands of the subject. Objects the subject is holding may be treated as background if they are not clearly connected. Check the result at full size and try a less extreme strength if the edges are noticeable.