Make a bar bending schedule (BBS) for an RCC column, from the footing to the roof, for a ground-floor house up to G+3. Enter the column size, the bars, the tie spacing and the heights from your drawing, and the calculator gives the cutting length of every vertical bar and tie, the laps at each floor, the number of ties and the steel weight by diameter. Part of our BBS calculators.
How to use the column BBS calculator
- Choose the number of floors: G, G+1, G+2 or G+3.
- Enter the column size (or tap a common size) and the clear cover.
- Enter the corner bars, any middle bars and the tie size, with the tie spacing near the floors and in the middle of each storey.
- Enter the floor-to-floor height, the height from the footing top to ground, the plinth height and the footing depth.
- Open Footing, laps and hooks to change the L-leg, the lap length, the top extension or the hook length.
- Enter the number of identical columns and any wastage, then download the schedule as CSV, print it or share a link.
Column BBS Calculator
Bar bending schedule for an RCC column from footing to roof: vertical bars, laps and ties
Footing, laps and hooks
Bar bending schedule
Steel by diameter
Checks
Educational BBS for quantity estimate. Bar sizes, numbers, cover, laps, tie spacing and confining zones must come from the structural drawing; this is not structural design or a detailing sign-off. Rules follow common Indian practice as used in the source sheets, with the corrections noted on the page.
Formulas used
| Bar | Cutting length or number |
|---|---|
| Vertical bar, first piece | L-leg + (footing depth − footing cover − 2 × footing mesh φ) + footing top to ground + plinth + storey height + lap (or top extension) − 2φ for the bottom bend |
| Vertical bar, each upper floor | Storey height + lap; the top floor gets the top extension instead of a lap |
| Lap and top extension | 50φ by default (change both to match your drawing) |
| Tie | 2 × (a + b) + 2 × hook − 2 × 3φ − 3 × 2φ, where a = B − 2c − φ, b = D − 2c − φ and the hook is 10φ (or 9φ) |
| Ties per storey | End zones of a quarter of the storey at the top and bottom: 2 × (zone ÷ close spacing, rounded down, + 1); middle half: (middle ÷ wide spacing, rounded up) − 1 |
| Ties below plinth | (Footing top to ground + plinth) ÷ close spacing, rounded up |
| Cross-tie for middle bars | Short side − 2c − φ + 2 × hook − 2 × 3φ, one per pair of middle bars at every tie level |
| Weight | φ² ÷ 162 kg per metre × total length |
φ is the bar diameter and c the clear cover, in mm. No ties are counted inside the footing; add them if your drawing shows them.
Worked example
A 230 × 300 mm ground-floor column with 40 mm cover, 4 bars of 12 mm and 8 mm ties at 100 mm near the floors and 150 mm in the middle. The floor-to-floor height is 3000 mm, the footing is 450 mm deep with 50 mm cover and 12 mm mesh bars, the footing top is 1200 mm below ground and the plinth is 450 mm high:
- Inside the footing: 450 − 50 − 2 × 12 = 376 mm.
- Vertical bars: 300 + 376 + 1200 + 450 + 3000 + 50 × 12 − 2 × 12 = 5902 mm each.
- Ties: a = 230 − 80 − 8 = 142, b = 300 − 80 − 8 = 212; 2 × 354 + 2 × 80 − 48 − 48 = 772 mm.
- Ties in the storey: 750 mm end zones give 2 × (7 + 1) = 16, the 1500 mm middle gives 10 − 1 = 9, so 25. Below the plinth, 1650 ÷ 100 rounded up gives 17. Total 42 ties.
Total steel: about 34 kg for one column (21 kg of 12 mm bars and 13 kg of 8 mm ties).
Frequently asked questions
How is the cutting length of column vertical bars calculated?
Add the L-shaped leg at the bottom of the footing, the height inside the footing (footing depth minus cover and the footing mesh bars), the height from the footing to ground, the plinth height, the storey height and the lap or anchorage at the top (often 50φ), then deduct 2φ for the bottom bend. For multi-storey columns each storey gets its own bar, lapped into the next.
How is the cutting length of a column tie calculated?
With a = B − 2 × cover − φ and b = D − 2 × cover − φ, a closed tie with two 135° hooks is 2(a + b) + 2 × hook length − 2 × 3φ − 3 × 2φ. The hook is usually taken as 9φ or 10φ. For a 600 × 300 mm column with 40 mm cover and 8 mm ties and 9φ hooks this gives 1496 mm.
Why are column ties closer near the floors?
The ends of a column, near the beams and slabs, carry the highest forces in an earthquake, so drawings usually call for closer ties there. A common simple scheme puts closer ties over a quarter of the storey height at the top and bottom and wider ties in the middle half; follow your drawing.
What is the minimum number of bars in a column?
IS 456 practice calls for at least four longitudinal bars in a rectangular column and six in a circular one, at least 12 mm in diameter. Bars along the faces between the corners need extra links or cross-ties so that every bar is held.
What lap length is used for column bars?
Column bars are joined at each floor by lapping, commonly about 50 times the bar diameter for Fe 500 bars, placed where the drawing shows. The calculator adds the lap to the lower bar of each joint; change the multiple to match your drawing.
Are footing starter bars part of the column BBS?
Yes. The first bar of a column starts with an L-shaped leg resting on the footing mesh, so the column BBS includes the length inside the footing. The footing mesh itself is scheduled separately.
More reinforcement tools
Beam BBS calculator
Main bars, extra bars and stirrups for beams and lintels.
Slab BBS calculator
One-way and two-way slabs: main, distribution and extra bars.
TMT bar weight calculator
Weight of any bar list by diameter and length.
Footing BBS calculator
Bottom and top mesh for isolated footings and rafts.
Retaining wall BBS calculator
Base slab and stem bars for cantilever RCC walls.
All BBS calculators
Slab, beam, column, footing and retaining wall schedules.
Disclaimer: Online educational publication only. Not a substitute for structural design or detailing by a licensed engineer. Full disclaimer · contact@speakarch.com
Last updated: 8 November 2026