How BBS cutting length is calculated
A bar bending schedule lists every bar with its shape, cutting length, quantity and weight. The cutting length starts from the bar's outline dimensions and is corrected for bends and hooks:
| Item | Rule (IS 2502) |
|---|
| 90° bend | deduct 2d |
| 135° bend | deduct 3d |
| Stirrup hook | add 10d per hook (min 75 mm) |
| Standard end hook | add 9d per hook |
| 45° crank | add 0.42 × D per crank (D = crank depth) |
Example — 8 mm stirrup for a 230 × 450 column (25 mm cover)
Stirrup outer size A × B = (230 − 2×25) × (450 − 2×25) = 180 × 400 mm.
Cutting length = 2(180 + 400) + 2×80 (hooks, 10d) − (3×16 + 2×24) (bends) = 1160 + 160 − 96 = 1,224 mm.
Weight = 1.224 m × 8²/162 = 0.48 kg per stirrup.
Frequently asked questions
How do you calculate the cutting length of a stirrup?
2(A + B) + 2 hooks (10d each, min 75 mm) − bend deductions (3 × 2d for the 90° bends and 2 × 3d for the 135° hook bends). Enter A and B above and the calculator applies all of it.
What is the extra length for a cranked bar?
0.42 × crank depth per 45° crank. A bar cranked at both ends with 150 mm depth adds 2 × 63 = 126 mm.
How is rebar weight calculated from cutting length?
Weight per metre = d²/162 (kg/m). Multiply by the cutting length in metres and the number of bars — the calculator shows the total automatically.
Is this BBS calculator free?
Yes — free with no login. For a complete BBS generated from your actual drawings, try SteelConnect's AI estimation (first estimate free).