A method for monitoring the amount of product harvested by an agricultural machine (10) including harvesting equipment (16) is proposed, which comprises the steps of storing a predetermined yield map (45) in memory means accessible by a processing unit (30), continuously providing positional data and sensor data to the processing unit while the agricultural machine (10) is in operation, wherein the positional data comprises information on a location of the agricultural machine (10) and the sensor data comprises information on a state of the harvesting equipment (16), and calculating the amount of product harvested based on the positional data, the sensor data and the predetermined yield map.
