The description of quality software metrics is presented. Based on a set of quality characteristics, specialized and application oriented characteristics systems are built. For each characteristic there are countless level estimation models, from which a significant one is debated. A model in which the codomain is between [0,1] is selected for each characteristic correlated with a high level of orthogonality in relation to other characteristics that are part of the system. An aggregate indicator with the codomain between [0,1] is built using weights that create a more comprehensive overview of software quality. The importance of defining techniques for weights calculation is presented. The properties obtained for the weights are analyzed using different techniques.