In this paper, we propose an adaptive and multi-sector-based user clustering algorithm which increases energy efficiency in a cellular network. Adaptive sectoring with dynamically changing sector angles is illustrated with a number of randomly distributed mobile stations. Transmitted power is equally shared by sectors before adaptive user clustering. The sector angles vary from 30 to 360 degrees by merging neighboring sectors and a sector is switched off till the user density exceeds a threshold (Td). The Td value is computed from the total number of users that the cell can accommodate over the area of the cell. The sectors with less than Td density exhibits transmit power which approaches to zero or sleeping state and so that the cumulative power is saved. Simulation results show that an average of 45% to 50% energy can be saved in 10 iterations.