Bar Bending Schedule of Beam: Worked Example
A beam bar bending schedule lists the bottom bars, top bars, extra bars and stirrups as separate marks, each with count, cutting length and weight. In this worked 230 × 450 mm beam, three 16 mm bottom bars and two 12 mm top bars are 5,600 mm each, and 21 stirrups of 8 mm are 1,225 mm each: 46.67 kg.
A worked quantity example, not a reinforcement design. Weights use D²/162 kg/m; link bends use site approximations explained below. Reviewed 20 October 2026.
One workbook with slab, beam, column and footing sheets. Change any dimension and the counts, cut lengths, weights and diameter totals recalculate. The PDF prints these four examples.
Worked beam: dimensions and scope
One 230 × 450 mm beam with a 4,000 mm clear span. B1 is three 16 mm bottom bars; B2 is two 12 mm top bars. Each runs straight 800 mm past each support face. B3 is an 8 mm closed stirrup at 200 mm maximum spacing along the whole span.
Cover is 25 mm to the outside of the stirrup. The first and last stirrup centres are 50 mm from the support faces. The 800 mm extension is a given dimension, not a calculated development length. Support extras, joint steel and curtailed bars are excluded, and uniform spacing is not seismic (ductile) detailing.
| Input | Value | Unit |
|---|---|---|
| Clear span between support faces | 4,000 | mm |
| Beam width | 230 | mm |
| Beam overall depth | 450 | mm |
| Cover to outside of stirrup | 25 | mm |
| Straight extension at each end | 800 | mm |
| B1 bottom diameter | 16 | mm |
| B1 bottom count | 3 | bars |
| B2 top diameter | 12 | mm |
| B2 top count | 2 | bars |
| B3 stirrup diameter | 8 | mm |
| B3 maximum spacing | 200 | mm |
| First/last link offset from face | 50 | mm |
| Nominal hook addition multiplier | 10 | d |
| Minimum nominal hook addition | 75 | mm |
| Cut-length rounding increment | 25 | mm |
Cutting lengths and bar counts, step by step
Each line puts the inputs above into one formula. ROUNDUP(x, 0) rounds up to a whole number and MAX takes the larger value. Bar counts include both end bars.
1. B1 straight cutting length
4000 + 2 × 800 = 5,600 mm
2. B2 straight cutting length
4000 + 2 × 800 = 5,600 mm
3. B3 first-to-last centre distance
4000 − 2 × 50 = 3,900 mm
4. B3 spaces, rounded up
ROUNDUP(3900 ÷ 200,0) = 20 spaces
5. B3 stirrup count
20 + 1 = 21 bars
6. Outside link width a
230 − 2 × 25 = 180 mm
7. Outside link height b
450 − 2 × 25 = 400 mm
8. Nominal addition H per end
MAX(10 × 8,75) = 80 mm
9. Outside rectangle perimeter
2 × (180 + 400) = 1,160 mm
10. Three 90° deductions
3 × 2 × 8 = 48 mm
11. Two 135° deductions
2 × 3 × 8 = 48 mm
12. Raw approximate link length
1160 + 2 × 80 − 48 − 48 = 1,224 mm
13. Scheduled link cutting length
ROUNDUP(1224 ÷ 25,0) × 25 = 1,225 mm
The link formula is the site shortcut: outside dimensions, hook H = max(10d, 75 mm), and bend deductions of 2d per 90° and 3d per 135° bend. Rounding up adds 1 mm, which goes into the hook ends without reducing cover.
Full BBS table for the stated example
The beam example totals 46.67 kg from 26 bars. Total length = count × cutting length ÷ 1,000; unit weight = D²/162 kg/m; weight = total metres × unit weight.
| Bar mark / position | Shape | Dia (mm) | No. of bars | Cut length (mm) | Total length (m) | D²/162 (kg/m) | Weight (kg) |
|---|---|---|---|---|---|---|---|
| B1Bottom longitudinal | Straight | 16 | 3 | 5,600 | 16.800 | 1.580247 | 26.55 |
| B2Top longitudinal | Straight | 12 | 2 | 5,600 | 11.200 | 0.888889 | 9.96 |
| B3Closed stirrup | Rectangle, two 135° ends | 8 | 21 | 1,225 | 25.725 | 0.395062 | 10.16 |
| Example subtotal | 26 | 53.725 | 46.67 | ||||
B1: 3 × 5,600 ÷ 1,000 = 16.800 m; 16.800 × 16² ÷ 162 ≈ 26.548148 kg → 26.55 kg.
B2: 2 × 5,600 ÷ 1,000 = 11.200 m; 11.200 × 12² ÷ 162 ≈ 9.955556 kg → 9.96 kg.
B3: 21 × 1,225 ÷ 1,000 = 25.725 m; 25.725 × 8² ÷ 162 ≈ 10.162963 kg → 10.16 kg.
Steel summary by diameter
| Diameter | Pieces | Total metres | Weight (kg) |
|---|---|---|---|
| 8 mm | 21 | 25.725 | 10.16 |
| 12 mm | 2 | 11.200 | 9.96 |
| 16 mm | 3 | 16.800 | 26.55 |
Unrounded row weights are added first, then the 46.67 kg total is rounded, so displayed rows can differ by 0.01 kg. Cutting waste is not included.
IS code checks and conventions used
The bend deductions and hook length below are site approximations; IS 2502, SP 34 and IS 13920 govern the approved bar shapes. The examples use the same marks and quantities as the BBS format and IS-code guide. A bar mark is only an identifier: IS 2502 clause 3.1 and SP 34 section 5 call for a dimensioned shape for each bar.
Dimensions
All inputs and cut lengths are in mm. Link dimensions are outside-to-outside. Cover is measured to the outer steel surface.
Do not put centreline dimensions into the outside-dimension link shortcut.
Bend deductions
Site approximations: 45° = 1d, 90° = 2d, 135° = 3d. Each closed link here has three 90° corners and two 135° hooks.
IS 2502 and SP 34 dimension each shape with its own allowances; neither gives one angle-only deduction table. Bend radius and steel type change the true value.
Hook extension / allowance
H = max(10d, 75 mm) per hook; for an 8 mm link, H = 80 mm.
10d (at least 75 mm) is the IS 13920:1993 hook extension, clauses 6.3.1 and 7.3.1. The 2017 amendment to IS 13920:2016 uses 8d (at least 75 mm). We keep 10d to match our BBS guide; use the edition your project specifies.
Approximate link length
2(a + b) + 2H − [3(2d) + 2(3d)], rounded up to the next 25 mm.
A site estimating shortcut, not a bend allowance from IS 2502. Fabricate to the approved shape and bend radius.
Bar counts
Ceiling(first-to-last centre distance / maximum spacing) + 1.
Both end bars are included. For a mesh, centre distance = overall size across the bars − 2 × cover − bar diameter. Count a bar on a shared zone boundary once.
Weight
Total length × D²/162 kg/m, kept at full precision until display.
A close approximation: 12 mm gives 0.888889 kg/m against 0.888 kg/m in IS 1786 Table 1. Bill on the basis your contract states.
Rounding and scope
Bent lengths round up to the next 25 mm; the straight lengths here already land on 25 mm. Weights show 2 decimals.
IS 2502 clause 5.1.1 and SP 34 clause 13.3.3.1 take the rounding excess into a portion named on the schedule. Waste, stock-length optimisation and bars not shown here are extra.
Sources checked
- IS 2502:1963 — clauses 3.1, 5.1.1 and Tables II–IX
Dimensioned shapes, allowances and cutting-length increments.
- SP 34:1987 — section 5 and clause 13.3.3.1
Bar marks, member schedules, sketches and the 25 mm scheduling increment.
- IS 13920:1993 — clauses 6.3.1 and 7.3.1
135° hook extension for beam and column hoops: 10d, at least 75 mm.
- IS 13920:2016, Amendment 1 (September 2017)
Reproduced BIS amendment (third-party copy): 8d, at least 75 mm, in beam clause 6.3.1(a) and column clause 7.4.1. Check the edition your project specifies.
- IS 1786:2008 — Table 1
Nominal mass per metre; differs slightly from the D²/162 approximation.
- IS 456:2000 — clauses 26.2 and 26.4
Development, laps and nominal cover; use the approved design values.
Common beam BBS mistakes
Using 230 × 450 as the stirrup size
Subtract cover twice: outside link dimensions are 180 × 400 mm.
Taking 800 mm as a universal anchorage
Use the actual support geometry and designer's development/anchorage detail for each bar size.
Using uniform spacing in a seismic support zone
Split the specified spacing zones and count a shared boundary link once.
Double-counting hook bends
Do not apply the outside-dimension deductions to a centreline-and-arc length or to an already complete hook allowance.
Use a checked BBS in your BOQ and billing
Carry BBS kilograms into the reinforcement BOQ item only after every bar on the drawings is accounted for. Keep the member, floor or pour, drawing revision, shape and checker with each schedule. For BBS from your full drawing set, get a BOQ from drawings below; for monthly BBS with measurement sheets and RA bills, use the construction billing desk.
FAQs: BBS of beam
Which bars belong in a beam BBS?
Every approved longitudinal mark, support extra, bent/curtailed bar, stirrup shape and relevant support bar. This exercise covers B1, B2 and B3 only.
What is the beam main-bar cutting length here?
B1 and B2 are straight: 4,000 + 800 + 800 = 5,600 mm each. Their different diameters and positions require separate marks.
How many stirrups are needed?
21. The centre distance is 4,000 − 50 − 50 = 3,900 mm, and ceiling(3,900/200) + 1 = 21 stirrups. Actual equal spacing is 195 mm.
How is the stirrup cutting length calculated?
With outside dimensions 180 × 400 mm and H = 80 mm: 2(180 + 400) + 2 × 80 − (3 × 16 + 2 × 24) = 1,224 mm, rounded up to 1,225 mm.
Is 10d the current universal 135° hook rule?
No. IS 13920:1993 specifies 10d with a 75 mm minimum. The 2017 amendment to IS 13920:2016 uses 8d with a 75 mm minimum for beam hoops. These examples keep 10d to match our BBS guide; follow the edition and detail your drawings specify.
Can I use 9d instead of 10d?
Not by swapping the number. The 9d in IS 2502 is the allowance for a semicircular (180°) hook in mild steel; it is not a 135° link hook extension.
Does 46.67 kg include cutting waste?
No. It is the theoretical weight of the three marks shown. Stock lengths, offcuts, support extras and procurement allowances are extra.