Wrapping reinforced concrete (RC) column with FRP sheets enhances compressive strength of column. Since stress- strain curve of concrete strengthened with FRP is different from that of normal concrete, common relation regarding normal column can not be used as designing columns strengthen with FRP. This research used stress-strain curve of confined concrete presented by researchers and ACI codes to design an algorithm for determining biaxial bending moment and axial load capacity of strengthened columns. To this end, the algorithm was implemented in Visual C#. Then, verification of this method was confirmed by comparing the result of this method to experimental results. Currently, common method for designing RC column strengthen with FRP is based only on controlling compressive strength. This means that if a wrapped FRP sheet together with concrete can provide a compressive strength of normal column, designing column strength is confirmed and this issue that stress-strain curve of normal column is different from that of confined, is neglected. Hence, the designing method was verified by programing. Results revealed that the designing method can be used prudently.