Chemical composition of lignocellulosic biomass (LCB) is an important parameter to be determined in order to identify the chemical potential in LCB. The compositional analysis of LCB is the first analysis performed prior to any LCB conversion process to produce high value-added products. LCB composition is generally characterized according to Laboratory Analytical Procedures (LAPs) published by National Renewable Energy Laboratory (NREL), USA. Major chemical components determined are glucan, xylan, arabinan, galactan, mannan, ash, extractives and lignin. The mathematical parts performed manually in the compositional analysis are tedious, complex and repetitive due to the interrelation of calculations within each chemical component. These manual calculations for each chemical component should be performed carefully and systematically to avoid errors in the final results of LCB composition. Therefore, this research work developed a computerized method to perform automatic LCB composition calculation system using Visual Basic (VB) software integrating its Graphical User Interface (GUI) concept to help users in performing the LCB composition calculation specifically for biomass-based research use.