Project detailsName, client, your steel rate
Only your own figure is used — InstaBOQ adds no rate.
A beam bar bending schedule lists the bottom main bars, the top bars, any extra bars over the supports or bent-up bars, and the stirrups that tie them together. Enter the beam size, clear span, cover, support width and bars to get the cutting length, count and weight of each. 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 × 450 mm beam, 4000 mm clear span
A 230 × 450 mm beam spanning 4000 mm clear between 230 mm supports, 25 mm cover, with 4 × 16 mm bottom bars and 2 × 12 mm top bars bent down into the supports, and 8 mm stirrups at 150 mm with 135° hooks, M25 / Fe500. 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 |
|---|---|---|---|---|---|---|---|
| B1/1 | Stirrup | Closed rectangle | 8 mm | A 180 B 400 H 80 | 1220 mm | 27 | 13.01 kg |
| B1/2 | Main bar | Bent down both ends | 16 mm | A 192 B 4410 C 192 | 4730 mm | 4 | 29.90 kg |
| B1/3 | Top bar (hanger) | Bent down both ends | 12 mm | A 144 B 4410 C 144 | 4650 mm | 2 | 8.27 kg |
Total steel 51.18 kg in 0.414 m³ of concrete.
- Anchorage at supports (main bar)
- Bars run 205mm into the support (width 230 − cover 25), then turn 90° for a 192mm leg (12d). For comparison the full development length is 777mm and this detail provides 205mm straight + a 90° bend (IS 456 Cl 26.2.2.1 counts a 90° bend as 8d = 128mm). IS 456 Cl 26.2.3.3 lets a simple support need less than the full Ld; whether this detail is enough is a design check this tool does not make.
How does the calculator work out each beam bar?
- Stirrup
- a closed rectangle measured outside to outside: A = b − 2 × cover and B = D − 2 × cover. Cutting length = 2(A + B) + two hooks − five bend deductions (three 90° corners at 2d and two 135° hooks at 3d).
- 135° hook
- 10d, but never less than 75 mm (IS 13920).
- Number of stirrups
- floor(clear span ÷ spacing) + 1, or counted zone by zone if you give closer spacing near the supports.
- Bars bent down into the supports
- each bar runs (support width − cover) into each support and turns down with a 12d leg; the two 90° bends are deducted at 2d each.
- Straight bars with full anchorage
- the other option: clear span plus the development length Ld = 0.87 fy × d ÷ (4 × 1.6 τbd) at each end (IS 456 Cl 26.2.1), not rounded to a whole d.
- Weight
- total length × d² ÷ 162 kg per metre, d in mm.
Bend deductions, hook lengths and rounding are listed in full under "Assumptions used" above.
Where can you learn the beam calculation step by step?
- Calculate a complete stirrup cutting length — a lesson in the free bar bending schedule course.
- Make bars reach with development length and laps — a lesson in the free bar bending schedule course.
- Produce and check a complete beam schedule — a lesson in the free bar bending schedule course.
Frequently asked questions
- How do you calculate the cutting length of a beam stirrup?
- Take the inside dimensions of the stirrup outside to outside, A = width less two covers and B = depth less two covers, add 2(A + B) and two hook lengths, then subtract the bend deductions: three 90° corners and two 135° hooks.
- How many bends does a beam stirrup have?
- Five: three 90° corners and a 135° hook at each end. Counting only the corners under-deducts and over-orders steel on every stirrup in the job.
- How far do beam bars go into the column?
- That is set by the drawing and the design. This calculator offers the two common details: bars run into the support and bend down with a 12d leg, or run straight for the full development length. It reports both lengths so the detail can be checked against the design.
- Can I add extra top bars and bent-up bars?
- Yes. Extra top bars over supports, bent-up bars, a second layer of bottom bars, side-face bars and closer stirrups near the supports are optional groups, each entered in full or left out.
Bar bending schedule for other members: slab · column · footing · every member type.