Economic measurement tools allow a quantification of social differences not only for modern societies, but also for prehistoric communities. The use of Gini indices and Lorenz curves for the much discussed Chalcolithic cemetery of Durankulak (Bulgaria) indicates an average increase in material items from 5000 cal BC onwards and a tendency of these items to be distributed somewhat more equally. Towards the end of the Chalcolithic sequence, however, strongly growing inequality was associated with lower average welfare. The steep increase in social inequality might be one of the main reasons for the collapse of Chalcolithic societies around 4100 cal BC in Durankulak, but also in other South East European regions.