Abstract: A method of billing charges incurred by a customer having a subscription account maintained by subscription billing management system. The subscription account specifies at least one subscription to be charged according to a defined rate plan and the rate plan includes charge objects having attributes such as a charge type, a trigger condition, a unit of measurement, and a cost per unit of measurement. The method includes defining a charge segment associated with a charge object, the charge segment being a time-based application of the charge object, and includes attributes such as its associated charge object and the charge object's attributes, an effective start time, a quantity of units, and a cost. The customers use of the subscription is monitored and charge events in are generated according to the defined charge objects and segments.