The intricate relationships that characterize the metabolism of urban areas need to be viewed through simplified formulas, so that they can support the decision-making processes leading to urban sustainability. In the framework of the Co-evolution paradigm (Norgaard, 1984) and the calculation of Material Flow Analysis and the Local Ecological Footprint regarding the Metropolitan Region of Santiago (Chile) and the city-region of Bogota (Colombia), Material Flow Analysis and the Local Ecological Footprint are shown as third-generation indicators binding, local, synergic and cross-cutting simultaneously incorporating several variables with broad categories and dimensions, and a high degree of contribution (80%) to the quantification of urban sustainability. The positioning of the local, through the local ecological footprint, also prevails in the improvement of indicators relative to the sustainability of a specific urban area, beyond the standardization of methodologies based on international comparisons or rankings.