Bar Bending Schedule Calculator

A Bar Bending Schedule (BBS) lists every reinforcement bar in a structural member with its shape, diameter, number, cutting length and weight. Contractors use it to cut and bend steel accurately, estimate quantities and reduce wastage. This calculator helps you work out cutting lengths and weights for common bar shapes.

How to use it

1. Select the member and bar shape, such as straight bars, bent-up bars or stirrups.
2. Enter bar diameter, member dimensions, clear cover, spacing and hook or bend details.
3. Review the cutting length, number of bars and total steel weight.

Key formulas

• Unit weight of steel: d² / 162 kg per metre, where d is the bar diameter in mm. A 12 mm bar weighs 144 / 162 = 0.889 kg/m.
• Bend deductions: commonly 1d for 45°, 2d for 90° and 3d for 135° bends.
• Hook length: typically 9d to 10d for a 135° stirrup hook in seismic detailing.

Worked example: rectangular stirrup

Beam 300 × 450 mm, clear cover 25 mm, 8 mm stirrups. Inner dimensions: 250 × 400 mm. Cutting length = 2 × (250 + 400) + 2 × 10d hooks - 3 × 2d (three 90° bends) - 2 × 3d (two 135° hooks) = 1300 + 160 - 48 - 48 = 1364 mm. Weight per stirrup = 1.364 × 64 / 162 = 0.54 kg.

Good practice

• Always follow the detailing code used on your project (for example IS 2502, BS 8666 or ACI 315), as bend deduction values differ.
• Add lap lengths for bars longer than the stock length, usually 12 m.
• Group identical bars to minimise cutting waste.