Industries are challenged to reduce CO2 emissions for carbon neutrality. One effective approach is using carbonfiber reinforced plastics to enhance fuel efficiency. This growing has increased the need for manufacturing monitoring to ensure high quality. This study presents a multi-stage real-time electrical resistance-based monitoring technique for resin transfer molding. The measured electrical resistances were analyzed to investigate the electromechanical behavior between resin and carbon fiber during manufacturing. Then, two decoupled monitoring strategies were introduced based on classification and quantitative methods. Real-time electrical measurement demonstrated that resin arrival was detected within 10 s, enabling accurate flow front prediction on the top surface and in the thickness direction using a developed model. The predicted filling time and resin flow behavior were validated through experiments and numerical analysis, resulting in a 4 % error. Although numerical simulations can provide an overall estimation of resin flow, the proposed real-time system offers a more precise and efficient method. Moreover, by utilizing a minimal number of electrodes on a large-scale panel, the proposed technique provides a cost-effective monitoring system with broad potential for resin transfer molding processes involving thermoset resins and closed-mold systems.