A system and method is disclosed for estimating demand of a supply chain including accessing a probability distribution of order lead time of the supply chain. The supply chain has nodes including a starting node and an ending node and a path from the starting node to the ending node. The probability distribution of order lead time describes ending node demand of the ending node versus order lead time. The path is divided into order lead time segments which are associated with the probability distribution of order lead time by associating each order lead time segment with an order lead time range of the probability distribution of order lead time. A demand percentage is estimated for each order lead time segment in accordance with the probability distribution of order lead time, such that each demand percentage describes a percentage of a total ending node demand of an order lead time segment.