The analysis of the structural model can be the most “black box” type phase of the design process for the engineer, and additionally the modern structural standards usually define the appropriate and required analysis type for the used design formula. The ConSteel applies the finite element method for all the calculations using two beam-column element types (traditional 12 DOF Timoshenko and 14 DOF thin-walled including warping of the section) and triangle shell element. The great variety of calculation possibilities includes first and complete second order (not only P-D effect) analysis; flexural-, torsional-, and lateral-torsional buckling solutions; local buckling analysis of slender steel members built from shell elements; static and dynamic eigenvalue analysis, buckling sensitivity analysis and earthquake calculation based on elastic response spectrum. The exceptionally fast and robust equation solvers yield optimal calculation time even for unusually huge models. The Structural Eurocodes defined a very high standard for the design of engineering structures which resulted in a huge and complicated collection of code regulations. This complexity is already untreatable without the aid of computer but at the same time allows the engineer to use different levels for the structural design. The design philosophy of ConSteel is to exploit the opportunity of using as many high level automated computer calculations as possible capitalizing the most state-of-the-art design formulas. The calculations of the design module cover the major part of steel design procedures (EC 3 1-1, 1-5, 1-8, EC 8) using the results of the global analysis for the cross-section and stability checks without the need of additional design parameters (buckling length, loading case etc.). After the automatic selection of the dominant load combinations and design formulas the colored graphical capacity view of the model spectacularly shows the weakest parts of the structure.