Simple analytical formulae have been reported in literature to extract basic elastic material properties of adhesives subjected to tensile loading. The assumptions and simplifications of classical evaluation procedures may result in a remarkable error depending on the investigated material combination. This work proposes a new evaluation procedure for the butt-joint test of adhesive technology. The main idea is to determine the deformed shape of the adhesive layer and to relate the deformation, i.e. contraction and elongation, to a unique set of Young's modulus and Poisson's ratio. A numerical parameter study for different combinations of adherend/adhesive materials and butt-joint geometries has been performed to investigate the influence of these parameters on the adhesive deformation. Comprehensive diagrams are derived which relate the deformation of the adhesive layer to the complete set of linear elastic constants.