The thermal power plants are used to generate power. The thermal power plants are designed based on required conditions, but actually inlet conditions are not as per the designed conditions. Variations in the power outputs from power plant are always a matter of disputes. So correction curves for power and heat rate are generated. In this paper, the thermodynamic analysis of 120 MW thermal power plant has been done at particular inlet pressure (124.61 bar) and at different inlet temperatures (507.78 C, 517.78 C, 527.78 C, 537.78 C, 547.78 C, 557.78 C and 567.78 C). The correction curves for power and heat rate have been generated for combined effect of inlet pressure and different inlet temperatures. These curves indicate that if inlet pressure is 124.61 bar and inlet temperatures vary, then power output and heat rate also vary. {\textcopyright} 2013 Elsevier Ltd.