Bar Bending Schedule (BBS) Calculator
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Updated
Pick a bar shape, enter its diameter and dimensions, and build a full schedule — cutting length, weight per bar and the total steel, rolled up by diameter. Cutting length follows IS 2502 (bends and hooks); weight is the standard D²/162 kg per metre. Your schedule saves on the device, so you can fill it in over a whole drawing, offline, on site.
Bar Bending Schedule (BBS) Calculator
Cutting length, weight and a full schedule — IS 2502 hooks & bends, D²/162 weight
Stirrup (135° hooks)
Cut length 1,216 mm · 0.480 kg/bar
0.395 kg/m
Per member
Beams/columns alike
Total steel in the schedule
0 kg
0 bar marks · +5% wastage ≈ 0 kg
Total steel
0 kg
Tonnes
0
Bar marks
0
With 5% wastage
0 kg
Schedule
Add bars above and they build up here into a schedule you can total and export.
IS 2502 bends and hooks: a 90° bend deducts 2d, 45° deducts 1d; a stirrup's 135° hooks add ~10d each. This tool folds the stirrup hooks and bends into the site-standard 2(a+b) + 7d. Order 3–5% over the schedule for offcuts, and cross-check against the drawing’s own BBS.
How the cutting length works
The cutting length is the straight length of bar before it is bent — the sum of the segments, minus the small amount saved at each bend:
- 90° bend deducts 2d, a 45° bend deducts 1d (d = bar diameter).
- A rectangular stirrup with 135° hooks uses the site-standard 2(a + b) + 7d, where a = B − 2·cover and b = D − 2·cover — the same formula as the stirrup cutting length page.
- Weight = cutting length (m) × D²/162 kg/m.
Worked examples
| Shape | Bar | Cutting length | Weight |
|---|---|---|---|
| Straight | 12 mm × 6,000 mm | 6,000 mm | 6 × 0.888 = 5.33 kg |
| L-bend | 16 mm, A 3,000 + B 500 | 3,000 + 500 − 2×16 = 3,468 mm | 3.468 × 1.580 = 5.48 kg |
| Stirrup | 8 mm, 230 × 450, 25 cover | 2(180 + 400) + 7×8 = 1,216 mm | 1.216 × 0.395 = 0.48 kg |
The 8 mm stirrup above, at 28 bars in one beam, comes to about 13.5 kg of steel.
Why a BBS matters
A bar bending schedule turns a drawing into a cutting and bending list the yard can work to — and a weight the store can order against. Getting the cutting length wrong on hundreds of stirrups wastes steel bar by bar; getting the bend deductions wrong makes every bar the wrong size after bending.
Frequently asked questions
What is the formula for cutting length of a stirrup? For a rectangular stirrup, 2(a + b) + 7d, where a and b are the internal dimensions (member size minus cover on each face) and d is the bar diameter — the 7d folds in the 135° hooks and bend deductions. An 8 mm stirrup in a 230 × 450 beam at 25 mm cover is 1,216 mm.
How do I calculate the weight of a steel bar? Weight per metre = D²/162, where D is the diameter in mm. Multiply by the cutting length in metres. A 12 mm bar is 0.888 kg/m, so a 6 m bar is 5.33 kg.
How much is deducted for a bend? A 90° bend deducts 2d, a 45° bend 1d, and a 135° bend 3d (IS 2502), where d is the bar diameter. These are already applied in the shapes above.
How much extra steel should I order? Add 3–5% over the schedule total for offcuts and wastage, then cross-check the figure against the drawing's own bar bending schedule.
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CivilSite Editorial Team✓ Engineer reviewed
Written and reviewed by practising civil engineers with 10+ years of Indian residential construction experience.