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A column bar bending schedule lists the vertical bars for each floor, with any lap carried up to the next floor, and the ties — closed rectangles plus single-leg cross ties where the bars need them. Enter the column size, floor height, cover and bars to get cutting lengths, counts and weight. The editor opens with the worked example below (unless you already have a schedule on this device) — change any figure, or add more members. Need it in Excel with formulas? Download the free bar bending schedule Excel template.
Nothing here yet. Add your first member. Each member is one beam, column, slab (and so on) with its bars; if you have six identical beams, add one and set "identical members" to 6.
The example is a beam, a column and a footing.
Assumptions used
- Bend deductions (× bar diameter, per bend)
- 45° = 1d, 90° = 2d, 135° = 3d (SP 34). If you give a bend radius, 45° and 90° bends use the exact geometric deduction 2(r + d)·tan(θ/2) − θ(r + d/2) instead; hooks always use the table.
- Hook length (× bar diameter)
- 90° = 12d, 135° = 10d
- Minimum hook length (IS 13920)
- 75mm floor, applied to the 135° hook only
- Unit weight (IS 1786)
- d² / 162 kg per metre
- Cutting lengths
- rounded half-up to the nearest 10mm, once
- Development length
- Ld = 0.87 fy × d / (4 × 1.6 × τbd), IS 456 Cl 26.2.1, used exactly — not rounded to a whole multiple of d, which can fall short of the code by up to half a diameter.
- Tie leg arrangements resolved
- 2 legs = 1 × closed_rect; 3 legs = 1 × closed_rect, 1 × single_leg; 4 legs = 1 × closed_rect, 2 × single_leg
- Stock length for splicing
- 12000mm. A bar longer than this is split into stock-length pieces and the lap steel at each splice is ADDED to the total length and weight — so for a spliced bar, total length is more than cutting length × bar count, by design.
- Splice lap length
- the greater of Ld and 30d (IS 456 Cl 26.2.5.1(c), flexural tension). If a grade pair has no tabulated bond stress, a bar needing a splice is reported as uncomputable rather than spliced with a zero lap.
- Closer stirrups / ties near the ends
- If you give an end-zone length and spacing, the run is counted as end zone + middle + end zone without counting the boundary bars twice. Zone lengths are never assumed.
- Bent-up (cranked) bars
- two 45° cranks, each adding 0.42 × the centreline offset D' (member depth − 2 × cover − bar diameter), on top of the anchored straight length. Centreline basis, so no extra bend deduction. Not yet hand-verified.
- Continuous beams
- Bottom bars per span: bent down into end supports, Ld/3 past the face at interior supports (IS 456 Cl 26.2.3.3(a)). Top bars continuous, bent down into both end supports, spliced with billed laps when over stock length. Not yet hand-verified.
- Column bars
- Floor height + lap carried up; a crank into the column above adds the slope length at 1 in 6; ground-floor starter bars add the footing depth less cover and an L-foot, with the 90° bend deducted. Circular columns: hoops are π × centreline diameter plus hooks; a helix adds 1.5 turns at each end.
- Lintel, staircase, pile cap
- Lintel bars run opening + bearing each side less cover; the stair is a one-flight waist slab with main bars along the slope (√(run² + rise²)); the pile cap is a plain block with a bottom mat and an optional straight top mat. Step concrete, pile heads and side-face bars are not modelled.
- Steel density ranges (kg/m³)
- beams 100–200, columns 150–280; other members are shown without a verdict — no published range has been checked for them, and a guessed range would be worse than none
A calculation aid, not a design. It applies standard IS conventions to the numbers you enter and does not check that they satisfy any code requirement. A qualified engineer must check and sign off the schedule before any bar is cut.
Worked example — 230 × 300 mm column, 3000 mm floor height
A 230 × 300 mm column, 3000 mm floor to floor, 40 mm cover, with 6 × 16 mm vertical bars and 8 mm ties at 150 mm — a closed tie plus one single-leg cross tie (three legs), M25 / Fe500. No lap is entered, so each vertical bar is one floor height. These figures are computed by the same code the editor above runs — they are not typed in.
| Bar mark | Bar | Shape | Dia | Dimensions (mm) | Cutting length | Total bars | Weight |
|---|---|---|---|---|---|---|---|
| C1/1 | Tie — closed rectangle | Closed rectangle | 8 mm | A 150 B 220 H 80 | 800 mm | 21 | 6.64 kg |
| C1/2 | Tie — single leg 1 | Single leg | 8 mm | A 150 H 80 | 260 mm | 21 | 2.16 kg |
| C1/3 | Vertical bar | Straight | 16 mm | A 3000 | 3000 mm | 6 | 28.44 kg |
Total steel 37.24 kg in 0.207 m³ of concrete.
- Inner leg span (tie_extent_mm)
- 150mm, derived as min(b, D) − 2 × cover = min(230, 300) − 2 × 40. This assumes the cross tie spans the shorter section dimension. Supply it explicitly if it crosses the other way.
How does the calculator work out each column bar?
- Vertical bars
- floor-to-floor height plus the lap you enter for the bars carried up to the next floor. Optional: a crank at 1 in 6 into the column above, and ground-floor starter bars running into the footing with an L-foot (the 90° bend is deducted).
- Closed tie
- the same rule as a beam stirrup: 2(A + B) + two hooks − three 90° and two hook bend deductions, with A and B outside to outside.
- Cross ties
- a single leg across the section with a hook at each end. The span it crosses is yours to give; left blank it is taken as the shorter side less two covers, and the page says so.
- Tie legs
- leg counts with one arrangement (2, 3, 4) are built for you. A count that can be built more than one way is refused rather than guessed.
- Number of ties
- floor(floor height ÷ spacing) + 1, or zone by zone with closer spacing at top and bottom.
Bend deductions, hook lengths and rounding are listed in full under "Assumptions used" above.
Where can you learn the column calculation step by step?
- Resolve column ties and leg arrangements — a lesson in the free bar bending schedule course.
Frequently asked questions
- How do you calculate the cutting length of a column tie?
- Exactly like a beam stirrup: A and B are the column sides less two covers, the cutting length is 2(A + B) plus two hooks, less three 90° bend deductions and two hook bend deductions.
- What lap length should I add to column bars?
- Use the lap shown on the structural drawing or in the specification. The calculator adds the lap you enter to every vertical bar; it does not choose one for you.
- Why does the calculator refuse some tie leg counts?
- Because a leg count alone does not say how the ties are built. Six legs can be a closed tie with two cross ties or two overlapping closed ties, and those use different amounts of steel. Read the arrangement off the column section on the drawing.
- Can I include starter bars into the footing?
- Yes. Give the footing depth, its bottom cover and the length of the L-foot, and the ground-floor vertical bars run down into the footing with the 90° bend deducted.
Bar bending schedule for other members: slab · beam · footing · every member type.