Steel Quantity Calculator
Calculate the reinforcement steel weight for reinforced cement concrete (RCC) columns. Enter the column dimensions, bar sizes, spacing and number of columns to generate a bar bending schedule with cutting lengths and total steel in kilograms.
Steel Quantity Calculator (BBS)
Planning aid, not a structural design. Bar sizes, development lengths and spacing must be confirmed by a qualified structural engineer against the governing code before construction.
Bare numbers are mm.
Bare numbers are mm.
Bare numbers are mm.
Bare numbers are mm.
Bare numbers are mm.
Bare numbers are mm.
Bare numbers are mm.
- Steel per column
- 41.97 kg
- Total steel
- 167.88 kg
- Total bar length
- 191.38 m
- Ties per column
- 27
167.9 kg of reinforcement across 4 columns.
How this was calculated
- Bar unit weight = d² / 162.2 kg/m
- Main bar length = height + ld(top) + ld(bottom) + beam cover − footing cover − 2 × footing bar dia − 2 × 90° bend deduction
- No. of ties = (height − beam cover − ld) / spacing + 1
- Stirrup cutting length = 2(a+b) + 2(hook) − 3(2d) − 2(3d), a and b = side − 2 × cover − d
- Weight = unit weight × total length
- Longitudinal bars (Ø16 mm) = 4.0 × 4.877 m × 1.5783 kg/m = 30.79 kg
- Lateral ties (Ø8 mm) = 27.2 × 1.040 m × 0.3946 kg/m = 11.18 kg
How to use the steel calculator
Enter the number of columns and the cross-section of each column (width and depth, in millimetres). Then specify the main bar diameter and how many main bars each column has, the tie diameter and spacing, and the column height. The calculator applies standard cover values (40 mm clear cover, 25 mm beam cover, 50 mm footing cover) and development lengths derived from the main bar diameter.
The result shows the steel per column, the total steel across all columns, the total bar length in metres, and the number of ties per column. A step-by-step breakdown shows the cutting length and weight for each bar group.
What you need to measure
Measure the column cross-section with a tape: width and depth are the two perpendicular dimensions of the column in plan. Height is the clear storey height from the floor to the underside of the beam. The main bar diameter is the size of the longitudinal bars (typically 16 mm or 20 mm). The tie diameter is the stirrup bar size (typically 8 mm). Tie spacing is the gap between stirrups, typically 150 mm.
Accuracy and limitations
This calculator produces a quantity estimate, not a structural design. It uses simplified formulas for cutting length and development length. Lap lengths, bends, anchorages and seismic detailing must be confirmed by a structural engineer against the governing code (IS 456 for India). The actual weight delivered by the steel supplier may differ by a small amount due to bar tolerances; add approximately 2-5% wastage when ordering.
Next steps
Use this calculator to estimate the steel quantity for a Bill of Quantities or for ordering. For a complete RCC estimate, combine it with the Concrete Mix Calculator on cement, sand and aggregate, or the Slab Concrete Calculator for slab-specific volumes and reinforcement. For the overall construction cost, use the India Construction Cost Estimator for a BOQ with material and labour rates.
Frequently asked questions
What is a bar bending schedule?
A bar bending schedule (BBS) is a table that lists every bar group in a structural element, the bar diameter, the number of bars, the cutting length, the shape code and the total weight. It is used by the steel fixer to cut and bend the bars on site, and by the quantity surveyor to measure the steel weight for billing.
How is steel weight calculated?
The weight of a bar is its total length in metres multiplied by its unit weight in kg/m. The unit weight is d2 / 162.2, where d is the diameter in mm. So a 16 mm bar weighs about 1.58 kg per metre.
What is development length?
Development length (ld) is the minimum embedment length needed to transfer stress from the bar to the concrete. A common rule of thumb is 40 times the bar diameter for tension bars. This calculator applies that for the top bars and a shorter value for the bottom bars.
How much steel is needed per cubic metre of concrete?
Typical RCC uses 80-120 kg of steel per cubic metre for columns, 100-150 kg/m3 for beams and 60-100 kg/m3 for slabs. Use the steel calculator for column-specific quantities.
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