Posture Checker Webcam

How the Posture Checker works

Posture checker webcam: getting a good result

Slouching is not something you notice while it happens; it creeps in over twenty minutes as your attention goes to the screen. What a posture monitor does is notice for you. This page runs a body pose model in your browser that finds 33 points on your body — nose, ears, shoulders, elbows, hips and so on — every frame from an ordinary webcam, and then measures a few simple things about how those points are arranged.

What "slouching" means to the tool. When you sit upright your nose is a certain height above the line between your shoulders. When you slump, your spine curves, your shoulders roll forward and your head drops towards the screen, and that height shrinks. The tool measures nose-to-shoulder height as a fraction of shoulder width, so moving closer to or further from the camera does not change it, and compares it with the value stored when you pressed Set upright baseline. Fall more than the sensitivity percentage below the baseline and you are slouching. Twelve percent is a reasonable default; lower it if you want nagging, raise it if it fires when you lean in to read.

The other three readouts. Shoulder tilt is the angle of the line between your two shoulder points, and a persistent tilt usually means one elbow is on the desk or the chair is lopsided. Head tilt is the same measurement between your ears. Head over shoulders is how far your nose is from the midpoint of your shoulders, horizontally, as a percentage of shoulder width; a consistent offset usually means the monitor is not in front of you. None of these needs a baseline, because level and centred are absolute.

Why a baseline at all. Cameras sit at different heights and people have different proportions, so there is no universal number for "upright". Calibrating against your own good posture makes the check personal and takes one press. Recalibrate if you move the camera or change chairs; press Reset and the baseline clears.

Limits. The camera needs to see at least your head and both shoulders, ideally your elbows too, and it works best straight on rather than from the side. Forward head posture — craning towards the screen without dropping — is the one habit this angle cannot see well, because the nose moves towards the camera rather than down; a side view catches it but then the shoulder measurements stop making sense. The model is a pose estimator, not a medical device, and the thresholds are conventions, not clinical values.

Privacy. The pose model runs in WebAssembly inside the page. The camera stream and the landmark positions never leave your browser; only the model itself, about 12 MB, is downloaded once and then cached.

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