Rebar Cutting Length Calculator

How it works

cutting length = sum of straight lengths + hook allowances − bend deductions · 90° hook: + 12d each end · bend deduction: 45° = 1d, 90° = 2d, 135° = 3d · crank: + 0.414 × crank height per crank · weight = d² ÷ 162 kg/m

Bar shapes on drawings are dimensioned to the outside of the bends, but a bar stretches round each bend, so the length to cut is the sum of the outside dimensions minus a bend deduction — about 1d for 45°, 2d for 90° and 3d for 135° bends (common bar-bending-schedule practice, e.g. SP 34). A standard 90° hook adds a 12d extension (ACI 318 §25.3). A bent-up bar inclined at 45° adds 0.414 × the crank height for each crank (√2 − 1). Weight per metre is d²/162 kg for d in mm, the mass of a steel rod at 7,850 kg/m³. Pieces per stock bar are counted without splicing; keep offcuts for short bars and chairs.

Worked example

Twenty 12 mm bars, 300 cm long with a 90° hook at each end: cutting length = 300 + 2 × 12 × 1.2 − 2 × 2 × 1.2 = 300 + 28.8 − 4.8 = 324 cm = 3.24 m. Weight = 12² ÷ 162 = 0.889 kg/m → 2.88 kg per bar, 57.6 kg in total. Three pieces come from each 12 m bar (1,200 ÷ 324 = 3.7), so buy 7 stock bars, with 228 cm of offcut each.

Sources: SP 34 Handbook on Concrete Reinforcement and Detailing (Bureau of Indian Standards) · ACI 318-19 §25.3 — Standard hooks

Frequently asked questions