["Canadian Journal of Administrative Sciences / Revue Canadienne des Sciences de l'Administration, Volume 43, Issue 3, September 2026. ", "\nABSTRACT\nThis paper proposes a novel approach to costing the Sustainable Development Goals (SDGs) by integrating traditional single‐sector models with advanced multi‐input frameworks. The method improves accuracy by addressing key limitations of conventional unit cost models, which often misestimate costs by neglecting interaction effects and nonlinear relationships. Using Egypt's fiscal data and SDG indicators for health, education and water and sanitation, the study quantifies the impact of sectoral spending and cross‐sectoral synergies. Results indicate that increasing expenditure alone is insufficient to achieve the SDGs. Instead, targeted and coordinated investments across sectors yield greater efficiency and impact. Under the optimal allocation scenario, Egypt can meet all six SDG targets analyzed at a total cost equivalent to 3.3% of GDP, compared with only partial achievement under the business‐as‐usual scenario. These findings highlight the importance of integrated policy design and strategic expenditure reallocation to accelerate sustainable development.\n"]