QuickCut

Blur the background of a photo

Keep the subject sharp and melt the busy bits behind it, like a fast lens would. Works on photos you’ve already taken.

No photo handy? Try one:

Runs in your browser. Your photos are never uploaded to a server.

Why your phone photos look “flat”

In a camera, background blur (shallow depth of field) comes from the optics. Every point that isn’t in focus is spread into a small disc, and the disc gets bigger with a wider aperture, a longer focal length and a larger sensor.

A phone’s main sensor is several times smaller than a full-frame camera’s, so for the same framing its lens has a much shorter real focal length, and the discs stay tiny. Most of the scene ends up in focus.

Try it in the model on the right: switch between the two cameras and see how much blur each would give at the same settings. When the optics can’t do it, software can: cut out the subject, blur only what’s behind.

Tips for a natural result

  • Stay subtle for headshots, around 8–14 px; heavy blur looks fake around hair.
  • Use more blur when the background is far away, less when it’s close behind the subject.
  • For products, try the blur with a tight square crop.

How much blur would a real lens give?

Background blur comes from the lens, not a filter: points behind the subject spread into discs whose size depends on aperture, focal length and sensor size.

Blur disc: 1.23% of the frame diagonal. Subject in focus at 2 m.

A phone sensor is roughly 5× smaller, so at the same framing its real focal length is 5× shorter and the blur disc shrinks about 5×. That’s why Portrait mode, and this tool, cut the subject out and blur the rest in software.

Questions people ask

How do I blur the background of a photo?

Drop your photo above. The AI separates the subject, and the background is replaced with a blurred copy of the original. Use the “Blur strength” slider to go from a subtle softening to a heavy portrait-lens look, then download.

Is this the same as Portrait mode on my phone?

It’s the same idea. Phone cameras have small sensors that can’t produce much natural background blur, so Portrait mode estimates which pixels are the subject and blurs the rest in software. This tool does that to photos you’ve already taken.

Why is there a glow around my subject after blurring?

Blurring spreads nearby colours, so a bit of the subject’s outline can bleed into the background. Lower the blur strength slightly, or move “Shrink/grow” toward Grow so the sharp subject covers the soft edge.

Can I blur the background for a video call?

Zoom, Teams and Google Meet have live background blur built in. This tool is for still photos: headshots, product pictures and social posts.

Does blurring the background hide private details?

A strong blur makes text and faces hard to read, but it isn’t a guaranteed redaction. For documents, number plates or addresses, cover the area with a solid colour instead.

Other jobs QuickCut does