Bar Bending Schedule Calculator & Steel Bar Weight

Mass and quantities

For nominal diameter $d$ in mm, use $w=d^2/162$ kg/m. A mark has $M=N L_s w$, with $L_s$ converted to metres. Counts describe longitudinal runs or individual links. An unspliced run is one bar; for a lapped run, $L_s$ is the aggregate steel length including all overlaps, not an individual splice-piece cut. The coefficient is declared with units; all length conversions are explicit. This is a site approximation, about 0.12% above the circular-area value at 7850 kg/m³, not a product mass certificate.

Bar counts

Slab main bars span the length and are counted across the width; distribution bars do the reverse. The transverse distance between first and last centres is $a=B-2c-d$. Each mesh has $N=\lceil a/s\rceil+1$ bars, redistributed at $a/(N-1)\leq s$. Identical layers and members multiply counts. Links use $N=\lceil (L-2o)/s\rceil+1$, where $o$ is the first/last centre offset.

Outside-dimension steel-length convention

$L_s=L_0+L_{legs}-L_{ded}+L_{lap}+L_{dev}$. Longitudinal end legs use the entered diameter multiple. Each bend deducts $k_\theta d$, defaulting to 1d, 2d and 3d at 45°, 90° and 135°. These are approximate takeoff deductions, not a claim that elastic stretching determines cut length. Bend diameter and fabrication convention can require different values.

For rectangular links, $A=b-2c$, $B=h-2c$ are outside dimensions. $L_s=2(A+B)+2\max(hd,h_{min})-(3k_{90}+2k_{135})d$: three 90° corners and two 135° hook bends. Gross hook allowances and bend deductions must belong to the same convention; do not subtract a hook bend twice from an already net allowance.

Laps add the explicit lap count × lap multiple × diameter. Additional development lengths use the selected count × development multiple × diameter; they are not designed here. Sum mark masses by diameter, then multiply by $1+p/100$ for wastage. See Civiconcepts for the site weight and bend rules, CivilOS for the 1244 mm worked link, and the attached IGNOU excerpt, page 3 (printed 163), for a 15-stirrup example.

Fit checks

Columns use one symmetric perimeter layer with four shared corners. Enter $n_x$ bars on each width face; $n_y=(n_c-2n_x+4)/2$ bars occupy each depth face. Both counts include their corners. The total must be even and both face counts at least two. Centre spans are $b-2(c+d_l)-d_c$ and $h-2(c+d_l)-d_c$. Each face's clear gap is centre span divided by its number of intervals, minus $d_c$; both gaps must meet the editable minimum. This verifies the chosen arrangement, not arbitrary packing or splice-zone congestion. The redistributed link centre spacing must be at least the link diameter.

• One rectangular slab panel with one or two identical orthogonal meshes; one beam bottom and top group; or one column vertical group with one bar size.
• Uniform spacing, with bars at both end stations. Clear cover is to the outer steel surface. Slab centre spans also subtract one bar diameter.
• Beam base lengths are overall member length minus twice cover. Column vertical base run is entered directly. Links use member width/depth minus twice clear cover.
• Bent end settings and additional development counts apply to every longitudinal mark in the selected schedule. Lap counts can differ between slab/beam directions.
• Gross hook and end-leg lengths use the outside-dimension approximation. Default link hooks are 135°, 10d with a 75 mm gross minimum, followed by the separate deductions shown. This convention is an estimating assumption, not verification of a seismic hook tail.
• Counts are longitudinal runs plus individual links, not physical splice-piece counts. For lapped rows the length per run is aggregate steel including overlaps. Separate splice pieces, their counts, overlap locations and staggering require a splice plan.
• Wastage is an editable procurement allowance, not a cutting optimization result. Diameters are nominal; rib geometry and rolling tolerances are excluded.
• Sketches show representative bars and symbolic bends. Their visible line count, bend radii and proportions do not replace the schedule or structural drawing.
• Column main bars occupy one symmetric perimeter layer: the total count is even, width-face counts are entered, and matching depth-face counts follow from the total. The minimum clear gap is editable. Check extra lap-zone bars, tie bend radii and local congestion separately.

Quantity takeoff only, within the stated input ranges and geometric conditions. No bending, shear, buckling, bond, crack-width, fire, seismic or structural adequacy check is performed. Supplied bar sizes and spacings must come from the structural drawing.

The bend-deduction practice is commonly associated with IS 2502:1963. Anchorage and lap detailing are governed by the applicable concrete and seismic rules, including IS 456:2000 and IS 13920:2016 where relevant. These editions name the methodological context reviewed on 26 October 2026; this calculator does not certify compliance. Check against the standard in force and the project's approved detailing convention.

For different hook conventions, revise both gross allowances and deductions together. Do not mix centreline lengths with outside lengths. Do not use a negative/zero cut or an over-stock run as a fabrication instruction. Detail individual splices and all unlisted marks separately. Reinforcement cutting, bending and placement must follow approved drawings and be checked by a qualified structural engineer or detailer.

The column fit check applies only to the explicitly defined symmetric single perimeter layer. It does not certify a different arrangement, cross-tie restraint or local lap-zone packing. The link-spacing guard checks physical non-overlap only; minimum code clearance and confinement spacing still come from the structural drawing.