Computation of drag force due to oscillation of a beam or any other solid structure near or away from the fixed surface is very important in controlling the performance of most microelectromechanical and nanoelectromechanical systems. Although there exist many formulations for drag-force computations near and away from the fixed bottom surface, they are limited to a single element. In this paper, we present a systematic formulation for arriving at a modified formula for drag force based on experimental and numerical simulations that can be used in computing forces in an array of microelectromechanical and nanoelectromechanical system beams. To develop the model, we first obtain an approximate analytical model for uniform as well as nonuniform motion of a cantilever beam. After validating the numerical model with experimental and analytical results for a single beam, we modify the formula to consider different boundary effects and then apply it to compute drag forces in an array of beams. Finally, we also modify the formulas to include the nearby wall effect. The formula developed works excellently when the interbeam gaps are small. However, the percentage error increases with interbeam gap and is found to be between 5% and 14%. © 2020 American Physical Society.