a method , a computer program , and an apparatus are provided for generating circuit energy models for a macro using multiple clock gating inputs . circuit energy models are used to estimate system power consumption . the present invention enables circuit energy models to be created for macros that contain multiple clock gating inputs . energy tables are created based upon the macro &# 39 ; s input switching factor and the clock activation percentage . the clock activation percentage is produced by turning on and off the multiple clock gating inputs during the simulations . these energy tables are generated from a minimum number of power simulations . by using clock activation percentage as a parameter accurate power estimations are produced .