Sheet product level sensor calibration and indication systems and methods

A sheet product (e.g., napkin) dispenser may include an example calibration system and method for a product depletion curve for accurately determining a product level. An example sheet product dispenser includes a housing, a roll holder, a dispensing mechanism, a sensor, and a controller. The sensor is configured to emit a signal toward the product roll and receive a return signal. The controller is configured to receive a calibration product roll and operate the sensor to emit the signal and receive the return signal. The controller determines a brightness value of the return signal and determines a calibration value associated with the determined brightness value. The determined brightness value is within a range of brightness values associated with the calibration value. The controller adjusts a product depletion curve based on at least the determined calibration value and the determined brightness value. Additionally, example product level notification systems are provided herein.