Generate accurate Bar Bending Schedules (BBS) instantly with our free online calculator. Built for civil & structural engineers, this tool follows IS 2502:1963 cutting-length formulas and IS 456:2000 lap-length standards — no signup required.
BBS Generator Pro — Online Calculator
Click the button below to open the full-screen BBS Generator, or use the embedded version right here on this page.
Tip: For the best experience on mobile, open the tool in full screen.
What is a Bar Bending Schedule (BBS)?
A Bar Bending Schedule is a detailed table that lists every reinforcement bar in a structural element — its shape, diameter, cutting length, number, and total weight. It is an essential document in reinforced concrete construction for:
- Accurate material estimation — prevents over-ordering or shortages of steel
- Cutting & bending instructions — bar fixers use it directly on site
- Cost control — steel is the most expensive component after concrete
- Quality assurance — ensures every bar matches the structural drawing
- Billing & measurement — the BBS is the basis for running-account bills
Features of Our BBS Generator
| Feature | Details |
|---|---|
| Bar Shapes | 10 shapes — Straight, Hook (1-end & 2-end), Bent-up (single & double), Crank, Rectangular Stirrup, Circular Stirrup, L-Bar, U-Bar |
| Cutting Length | Automatic calculation per IS 2502:1963 with step-by-step formula display |
| Lap Length | IS 456 tension (40d) and compression (24d) lap support with configurable multiplier |
| Weight Calculation | d²/162 kg/m formula, individual + total weight with configurable wastage % |
| Multiple Elements | Add Footing, Column, Beam, Slab, Staircase, Retaining Wall, or custom elements |
| Export Options | PDF report, CSV spreadsheet, and browser Print |
| Save & Load | Save projects as JSON files + automatic localStorage backup |
| Summaries | Element-wise, diameter-wise, and grand-total summaries |
Cutting Length Formulas (IS 2502:1963)
The tool uses the following standard formulas to compute cutting length for each bar shape:
| Shape | Cutting Length Formula |
|---|---|
| Straight | CL = L |
| Hook (one end) | CL = L + 9d |
| Hook (both ends) | CL = L + 18d |
| Bent-up 45° (single) | CL = L + 0.42h |
| Bent-up 45° (double) | CL = L + 0.84h |
| Crank | CL = L + 0.42h |
| Rectangular Stirrup | CL = 2(a + b) + 20d, where a = W − 2c, b = D − 2c |
| Circular Stirrup | CL = π(D − 2c) + 20d |
| L-Bar | CL = A + B − d |
| U-Bar | CL = 2A + B − 2d |
Where d = bar diameter, h = bend height, c = clear cover, W = member width, D = member depth, and L = member length.
Standard Bar Weights (d²/162 kg/m)
| Diameter (mm) | Weight (kg/m) | Diameter (mm) | Weight (kg/m) |
|---|---|---|---|
| 6 | 0.222 | 20 | 2.469 |
| 8 | 0.395 | 25 | 3.858 |
| 10 | 0.617 | 28 | 4.840 |
| 12 | 0.889 | 32 | 6.321 |
| 16 | 1.580 | 36 | 7.990 |
How to Use the BBS Generator
- Add a structural element — select from Footing, Column, Beam, Slab, etc., and give it a name (e.g., “F1 — Isolated Footing”).
- Choose bar shape — pick from 10 standard shapes. The tool shows a dynamic SVG diagram of the selected shape.
- Enter dimensions — fill in length, diameter, number of bars, and shape-specific parameters (bend height, cover, etc.).
- Add lap length (optional) — enable the lap-length toggle and specify the number of laps; tension (40d) or compression (24d) factors are applied automatically.
- Click “Add Bar” — the bar appears in the schedule table with its computed cutting length, total length, and weight.
- Repeat for every bar in every element. Use the Duplicate button to quickly copy similar bars.
- Review summaries — element-wise and diameter-wise breakdowns appear automatically.
- Export — download the schedule as a PDF report, CSV file, or use browser Print.
Frequently Asked Questions
What Indian Standard governs cutting-length formulas?
IS 2502:1963 — “Code of Practice for Bending and Fixing of Bars for Concrete Reinforcement” — provides the standard bend deductions and hook allowances used in BBS preparation across India.
How is bar weight calculated?
The unit weight of a reinforcement bar is d²/162 kg/m, where d is the nominal diameter in millimetres. This formula derives from the density of steel (7850 kg/m³) and the cross-sectional area (πd²/4).
What is a standard hook and what length does it add?
A standard hook (180° bend) adds 9d (9 × bar diameter) to the cutting length per IS 2502. If hooks are provided at both ends, the addition is 18d.
How is lap length determined?
Per IS 456:2000, the lap length in tension is 40d (or the development length Ld, whichever is greater) and in compression it is 24d. For bundled bars in tension the requirement increases to 2 × 40d. The minimum lap length in all cases is 300 mm or 15d.
Can I save my BBS and continue later?
Yes. The tool automatically saves your work to your browser’s local storage. You can also download a JSON project file and load it on any device later.
Is the tool free to use?
Yes — the BBS Generator Pro is completely free. No signup, no login, no usage limits.