This paper presents a structural design capacity checker that has been developed by using Microsoft Excel in order to carry out the calculations of simply supported beam as based on Eurocode 2. The purpose of this research is to develop an Excel User Interface and to perform structural design adequacy check of simply-supported beam under construction at the site. Besides, the required formulations for main reinforcement, shear, deflection and cracking checks are also programmed. The results of maximum shear force, maximum bending moment, tension and compression bars provided in Excel User Interface and STAAD Pro are compared. There are four main parts in Excel User Interface which are input, output, detailed calculation and data sheet. Input and output are the visible parts whereas detailed calculation and data sheet are hidden. In the output sheet, graph of shear force and bending moment, tension and compression bars provided, adequacy of main and shear reinforcement, deflection and cracking checking are shown. Another design of simply supported beam is designed by using STAAD Pro. The results that obtained from Excel User Interface and STAAD Pro is compared. This research helps users to carry out a structural capacity checking of simply supported beam in simple, precise and quicker.