Plain concrete is weak in tension. Reinforced concrete is produced by placing steel in the tension zone of the concrete beam. It is very widely used for construction of buildings and bridges. The calculator presented here can be easily used to find strength of singly as well as doubly reinforced concrete beam. This calculator is based on the guidelines of ACI-318 (American Concrete Institute’s code for design of reinforced concrete) . You can select the calculator as per your choice of system of units e.g. SI/metric or FPS/US-customary units.