<p>The ACI-318 code presents span-to-depth ratio expressions for solid, non-prestressed one-way slabs to control deflection when the impact on nonstructural items is not significant. These expressions relate slab thickness to span length, incorporating adjustments for steel yield strength and concrete density. However, they do not account for key design factors such as live load and concrete compressive strength, often resulting in conservative slab thickness estimates where the minimum reinforcement ratio is used. The adoption of the Bischoff formula for the effective moment of inertia in ACI-318-19 has further increased predicted deflections compared to the previous Branson formula, necessitating a review of span-to-depth ratio accuracy for deflection control. This study evaluates the compatibility of existing span-to-depth limits with deflections predicted using the Bischoff formula and proposes a new, efficient span-to-depth ratio formula for one-way slab design. The proposed expression incorporates key design factors, including concrete compressive strength, live load, and span length. A parametric analysis was performed to assess the influence of these parameters, and the new formula was derived based on deflection calculations and ACI-318 deflection limits. The suggested span-to-depth ratio is advised for slabs that do not support or connect to elements vulnerable to damage due to excessive deflections. Verification through case studies demonstrates that the predicted deflections using the proposed formula remain within ACI-318 limits while achieving more efficient designs with reduced slab thickness.</p>