Accurate estimation of metal accumulation in electric arc furnaces (EAFs) is critical for maintaining stable ferrosilicon (FeSi) production and ensuring effective process monitoring. Direct measurement of accumulated metal is currently not feasible due to extreme operating temperatures and the uneven distribution of molten material at the bottom of the furnace. Consequently, accumulation must be estimated through theoretical calculations, which directly influence production planning and operational decisions. This study proposes an improved methodology for approximating metal accumulation based on an enhanced mass balance formulation. Several modifications were introduced to increase estimation accuracy and responsiveness to process dynamics. The proposed improvements result in a smoother and more stable moving average of metal accumulation. Additionally, comparisons with theoretical input–output balances demonstrate improved consistency with expected furnace behaviour. The methodology provides a reliable estimation tool that can support operational decision-making and enhance production control in industrial EAF processes.