Preparation of Bar Bending Schedule
Bar bending schedule (or schedule of bars) is a list of reinforcement bars, vis-à-vis, a given RCC work item, and is presented in a tabular form for easy visual reference. This table summarizes all the needed particulars of bars – diameter, shape of bending, length of each bent and straight portions, angles of bending, total length of each bar, and number of each type of bar. This information is a great help in preparing an estimate of quantities.
Figure 1 depicts the shape and proportions of hooks and bends in the reinforcement bars – these are standard proportions that are adhered to:
(a) Length of one hook = (4d ) + [(4d+ d )] – where, (4d+ d ) refers to the curved portion = 9d.
(b) The additional length (la) that is introduced in the simple, straight end-to-end length of a reinforcement bar due to being bent up at 
say 30o to 60o, but it is generally 45o) = l1 – l2 = la
Where,
Fig: Hooks and bends in Reinforcement
Giving different values to 
respectively), we get different values of la, as tabulated below:
Figure 2 presents the procedure to arrive at the length of hooks and the total length of a given steel reinforcement.
Fig: Typical Bar Bending Schedule
Read More on Reinforcement Guide