We analyse the stress state of built – up timber columns by the standard for the design of timber structures SIST EN 1995-1-1. Columns are pin jointed at both ends. The cross - sections in a centrically compressed columns should be symmetrical so that the compressive stress over the entire section does not change. The computer program, created with the tool Microsoft Excel, allows the selection of the “boxed” and "I" section, which are the most common and effective for dimensioning built - up columns. The load capacity of a column mainly depends on its relative slenderness and rigidity of the connection between wooden elements, provided by the mechanical fasteners. Properties of the built -up column are captured by the effective bending stiffness and the slip modulus of mechanical fasteners. Shear connectors are wood - wood type and have one shear plane in which, when load is applied, the shear stress occurs. This shear stress is taken by the nails through their shear resistance. Fasteners are selected based on the type of wood, the cross - section dimensions and size of the load that fasteners have to bear. Based on the given geometry of the element, selected wood species, the applied time and size of load, the carrying capacity of elements, regarding column buckling and fasteners carrying capacity is checked. The program gives the results of the analysis of the selected column, separately for both load conditions, so that the user can correct only those parameters that do not meet certain conditions of the controls.