Systems, methods and articles that provide dynamic calibration of eye tracking systems for wearable heads-up displays (WHUDs). The eye tracking system may determine a user's gaze location on a display of the WHUD utilizing a calibration point model that includes a plurality of calibration points. During regular use of the WHUD by the user, the calibration point model may be dynamically updated based on the user's interaction with user interface (UI) elements presented on the display. The UI elements may be specifically designed (e.g., shaped, positioned, displaced) to provide in-use and on-going dynamic calibration of the eye tracking system, which in at least some implementations may be unnoticeable to the user.