A simple upper-bound strip technique has been devised as a development of the upper-bound element technique for the prediction of the spread in flat-tool indentation. A kinematically admissible velocity field for three-dimensional deformation is proposed. From the derived velocity field the upper-bound load and the deformed configuration are determined by optimizing some parameters. The theoretical estimates of forging load and deformed configuration are found to be in good agreement with experimental results and with rigid-plastic finite-element method results published in the literature. This technique can therefore be incorporated into forging-die CAD software for simulating and predicting the metal flow in cavities, which is mainly done by FEM and which until now has been a time-consuming process.