<p>The disassembly of end-of-life products offers significant benefits for both manufacturers and the environment by recovering reusable parts and materials. Disassembly planning is essential but complex, especially with increasing part numbers. Design for Disassembly methods aim to integrate disassembly considerations during product design. However, existing tools often lack simplicity and direct applicability for designers. This study proposes an objective Disassembly Complexity Index focusing on product structure and connections, aiming to provide quick and usable feedback for designers and engineers. The proposed index considers factors, such as component geometry, material, and liaisons, providing an objective assessment of disassembly complexity. By automating the calculation of factors, such as handling complexity and removal difficulty, the index streamlines the process and enhances reliability. A case study, through both the first analysis and the redesign, demonstrates the effectiveness of the index, offering insights into its main strengths: (i) computing time reduction, (ii) error reduction, (iii) increased resolution, (iv) results objectivity, (v) analysis repeatability. This approach contributes to product design optimization, compliance with regulations, and improved end-of-life treatment, aligning with sustainable manufacturing practices. The next steps will keep on working on objectivity and the automatic definition of the index; future works may (i) further investigate the rating resolution; (ii) study the automatic retrieval of geometric parts information; (iii) prove the validity and objectivity of parameters by comparing the tables contents and real effort evaluated through dedicated tools (i.e., electromyograph).</p> Graphical abstract <p></p>