1. A dishwasher comprising: means for detecting both a voltage change of a circulating pump and a heat increase in the dishwasher during at least a pre-washing phase and a heating phase; and a programme control in which the detected values are compared with stored target values, the programme control being operable to determine a quantity of dishes in a washing container of the dishwasher as a result of the detected-target value comparison and to adapt the washing programme according to the quantity of dishes detected.