Precise chip-level timing requires careful modeling of the interaction between logic drivers and interconnect. Existing static-timing analysis methodologies generate models for drivers with lumped capacitive loads. This necessitates the translation of the actual loading and interconnect parasitics into a single effective capacitance. Existing approaches to perform that translation are either iterative in nature or involve iterative procedure to solve non-closed form equations and thus costly in CPU time. This paper presents a new accurate and simple closed form approach to deal with effective capacitance.