Assume diameter of column at 400 mm

Clear cover 40mm also add half dia of bar of stirrups to get effective cover. ( say dia of bar is 10 mm then effective cover would be 40 +5=45 mm)

Stirrups bar dia assumed as 10 mm

For hook consider 10d or 75mm whichever is higher.

In circular stirrups degree of bend is considered at 135 degree. so bend = 3d

Formula:

**Cutting length of stirrup = Circumference of stirrup + 2 nos of hook - 2 nos of 135-degree bend**

The circumference of stirrups =2 pi R

Diameter assumed = 400 mm

Radius (r) = d/2 = 400/2=200mm

Radius of stirrups = 200 - 45 =155mm

So now lets calculate : (2 x 3.14 x 155) + (2 x 10 x 10) - ( 2 x 3 x 10) = 973.40 + 200 - 60 = 1113.40 mm

So for a column of 400mm dia the cutting length of stirrup in the above case is 1113.40 mm **say 1.11 meter**

Attached pls find calculator