India’s demographic landscape is entering a critical phase, marked by uneven transitions across its 28 states and increasing pressure on natural and social resources. This study introduces the Demographic Transition and Resource Planning Index (DTRPI), a novel composite framework that integrates demographic metrics, resource sustainability indicators, and socio-economic stability measures into a single decision-making tool. Unlike traditional demographic studies that treat population change and resource planning separately, the DTRPI unifies them to provide a predictive, evidence-based system for policymakers. The index highlights six states facing acute demographic and resource stress, with Jammu & Kashmir and Assam already at critical thresholds. By combining fertility patterns, migration trends, land and water availability, healthcare and educational infrastructure, and governance indicators, the framework not only identifies emerging risks but also suggests targeted, state-specific interventions. A projected investment of ₹2,500 crores demonstrates a high return ratio of 6.3:1 within five years, underscoring the economic feasibility of proactive planning. The novelty of the DTRPI lies in its integration of demographic transitions with sustainability and governance factors, creating an actionable, scalable model that can guide both national and international strategies. By offering an early warning system and a resource optimization roadmap, this framework moves beyond descriptive analysis to establish a new paradigm for managing India’s demographic future.