The subject of the thesis is the calculation of a reinforced concrete building located in Zagreb. Building consists of a ground floor and two floors, irregular floor plan shape and the largest floor plan dimensions are 12,70 m x 11,70 m and a total height 8,40 m. The top of the building is shaped by a flat roof. All bearing elements of the building are made of concrete class C30/37 and are reinforced with reinforcing steel B500B quality. Based on the given floor plan and basic dimensions, the overall shape of building was created. A 3D model of the building was created in the SCIA Engieer 22 software, after the assignment of vertical and horizontal loads base on the load analysis, a static and dynamic calculation has been conducted. Calculation and dimensioning of all load bearing elements, named: striped footings, slabs, beams, staircase, walls, reinforcement plans, was carried out by combining software and analytical calculations. The behavior of the structure under the action of an earthquake is presented. Final dimensions of the elements and the required amount of reinforcement are obtained by dimensioning, in addition to simplified architectural plans, at the end of the work, reinforcement plans for all of the above elements are presented.