Accuracy depends heavily on lighting, webcam quality, and head stability; expect roughly 150–300px screen error even after calibration, worse without a stable head position.
Head-position correction uses a simple nose-tip proxy, not true 3D head-pose tracking.
Gaze coordinates are relative to the browser viewport, not the full OS screen.
Blink and outlier filtering reduce, but do not eliminate, noise.
Reported fixation/saccade metrics are approximations, not clinically validated measurements.
Do not use this tool for medical diagnosis, clinical assessment, or safety-critical decisions.
For best calibration accuracy
Sit close to your webcam — about 1 foot (30cm) away. This gives the eye-tracking model far more pixels to work with, which noticeably improves accuracy.
Keep your head as still as possible for the whole calibration sequence.