We discuss the results of selected projects where we estimate the strength of aromatic stabilization with the
help of the Energy Decomposition Analysis within the Density Functional Theory framework. The paper introduces a new methodology to quantify the relative strength of aromaticity in aromatic and antiaromatic organic compounds. The approach
is also useful for the study of homo(anti)aromatic systems and for compounds where the traditional methods do not give a consistent answer concerning their aromatic character such as small-ring compounds and metallabenzenes.