Most of organizations today use information-communication technologies (ICT) for building an information system (IS). IS is assembled of hardware, software, network resources, organizational and human resources. In IS development process, complexity is crucial for evaluating quantities of resources needed (time, people, money, equipment). Complexity of an IS can be evaluated and/or measured in different phases of development. There are many methods for measuring complexity, but mostly used and thoroughly described method is Function Point Analysis (FP). The opposite method, Database Complexity (DC), does not measure all the aspects of IS, but it could evaluate system complexity depending on the database complexity. DC method is intended to be used for measuring semantic complexity of the IS database, and can be shown by counting attributes A and foreign keys F. This paper describes a very high correlation between FP and DC methods, and defines a function which can in 95% of accuracy express FP values from measured DC values.