A liquid intake tracking device for removable insertion into a beverage container in order to track an amount of liquid consumed, the rate of liquid consumption over time, and to provide alerts to the user. The device connects wirelessly to an application executing on an external electronic device which provides user with liquid consumption data and reports concerning the user's interaction with the beverage container. Methods for tracking liquid intake include disposing such a device within the container, calibrating the device relative to the container by processing pressure readings while the container is in an empty and full state, detecting changes in pressure within the container after the calibration step, in which the pressure is a function of a proportion of amount of liquid within the container at the time of detection, and wirelessly transmitting the measured pressure information to the external electronic device using a wireless communication module.