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R/FREE TOOL

Bar bending schedule calculator.

Build a BBS from slabs, beams, columns and footings, or bar by bar. Cutting lengths come from the actual bend geometry, every step is shown, and the schedule exports to Excel.

Step 1: Describe each element

Pick the element, type in the sizes and bars from your drawing, and add it to the schedule. Repeat for every footing, column, beam and slab. The numbers shown are an example; replace them with yours.

Bottom mat both ways. Bars run the footing dimension less cover; count = (width − 2 × cover) ÷ spacing, rounded down, + 1. Turning the ends up makes each bar a U-bar with legs of the thickness less two covers; the upper layer's legs are one bar diameter shorter.

F1: 13 × 12 mm · F2: 13 × 12 mm

Step 2: Check the schedule

Every bar from step 1 lands here as a row. Edit anything to match the drawing, press ? on a row to see how its cutting length was worked out, and add any bar the wizards don't cover with + Add a bar.

No bars yet. Add them from an element in step 1, or by hand below.

Want to see a finished schedule first? (4 footings, 4 columns, 2 beams, 1 slab).

Saved in this browser as you work.
Bending assumptionsIndia: IS 456 / IS 13920 · radius 4d / 4d · 135° hooks, 6d tail

Inner bend radius 4d for deformed (HYSD) bars, as in IS 456 Fig. 1; 135° hooks with a 6d tail, at least 65 mm, as IS 13920 requires for links. The drawings and the code that governs the job come first; every cutting length updates when you change these.

S-01/SHAPES7 SHAPES

Shapes and their dimensions

  • AStraight barSlab and footing bars, column and beam bars without end bends.A: length
  • AStraight with hooksBars anchored with a hook at each end.A: length, outside of hooks
  • BAL-barBars with one 90° bend: footing bars, wall starters, column dowels.A: leg a · B: leg b
  • ABCU-barBars with two 90° bends: slab edges, wall ends, top bars hooked into supports.A: leg a · B: width b · C: leg c
  • ABStirrup / linkClosed rectangular links for beams and columns, with a hook at each end.A: width, outside · B: depth, outside
  • ACHCranked barBent-up bars: a bar that rises over a support at an angle.A: bottom length a · H: rise h, outside · C: top length c
  • P, HDSpiral (helix)Helical reinforcement for piles and circular columns.D: centreline diameter · P: pitch · H: height of spiral
S-02/HOW IT WORKSGEOMETRY

Cutting length from the bend geometry

Schedules give outside dimensions: each leg is measured to the outer face of the bar at a bend. The bar itself does not reach that corner. It follows a curve around the former, so the straight dimensions overstate the length of steel needed. The difference is the bend deduction.

For a bend through angle θ with inner radius r on a bar of diameter d, the two outside dimensions each run (r + d) × tan(θ/2) past the start of the curve, while the bar's centreline follows an arc of θ × (r + d/2). The deduction is the first minus the second. Hooks are handled the same way: the arc and the straight tail are added, and the part of the corner already inside the leg's dimension is taken off.

Fixed allowances like “2d per 90° bend” are this formula at one particular radius. Calculating it keeps large bars, tight formers and non-standard angles right.

Bend deduction as a multiple of bar diameter
Inner radius45° bend90° bend135° bend
2d0.52d2.07d8.59d
3.5d0.59d2.72d12.30d
4d0.61d2.93d13.54d

Deduction per bend for legs given as outside dimensions. Multiply by the bar diameter. When the drawing's bars are scheduled, cut them with the cutting optimiser and check unit weights in the rebar weight charts.

S-03/QUESTIONS5

Add the outside dimensions of every leg, subtract a deduction for each bend, and add the length of any hooks. The deduction exists because outside dimensions run to the corner, while the bar itself follows a curve around the bend. This calculator works the deduction out from the bend radius and angle rather than using fixed allowances.

For a closed rectangular link: 2 × (width + depth) on outside dimensions, minus three 90° bend deductions, plus two hooks. An 8 mm link of 200 × 400 mm outside comes to 1,350 mm with IS 456 bending (4d radius, 135° hooks with a 6d tail, at least 65 mm). The bending rules selector switches to BS 8666 or ACI 318 values.

It depends on the bend radius. With an inner radius of 2d, a 90° bend deducts 2.07d, which is where the common 2d allowance comes from. With 3.5d it deducts 2.72d, and with 4d, the IS 456 radius for deformed bars, 2.93d.

A 180° hook with a 4d tail on a 2d bend radius adds about 13.1d to the bar beyond the outside dimension, close to the 9d allowance many schedules use. Set the hook angle and tail in the bending assumptions to match your drawings.

No. The schedule gives bars as detailed. Add laps as rows or as extra length where the drawings show them, and allow for wastage when ordering. The cutting optimiser shows the actual offcut for a given stock length.
ARCHED / ESTIMATING

Have a whole project to schedule?

A calculator handles the bars you type in. A project needs every member on every drawing, laps placed where the code allows, and the schedule revised when the drawings change. Send the reinforcement drawings and we return the full BBS in Excel, checked and signed off by an engineer.