Calculate Rectangular Hollow Section steel weight per metre and per piece instantly — standard box formula or accurate corner radius method as per IS 4923:1997.
Enter the rectangular hollow section dimensions, select formula mode and material — weight results update instantly.
Get accurate rectangular hollow section weight results in under 30 seconds
Select Standard Formula for a quick sharp-corner calculation — useful for quick estimates. Use With Corner Radius for accurate IS 4923-based results that match manufacturer catalogues.
Enter the outer height and outer width of the RHS in millimetres. For example, a 100×50 RHS has H = 100 mm and B = 50 mm. Use the nominal IS 4923 designation size.
Type the wall thickness (t) in mm. Common IS 4923 thicknesses: 2, 2.5, 3, 4, 5, 6, 8 mm. Always verify from your BIS certified Mill Test Certificate.
In Corner Radius mode, enter the inner corner radius ri. For IS 4923 sections, ri = 1.5 × t is the standard. For a 4 mm thick section, enter ri = 6 mm. Leave at 0 for sharp-corner calculation.
Enter the piece length in metres. Standard lengths in India are 6 m and 12 m. Set quantity for the total order weight. Results update live as you type.
Cross-check your kg/m result against SAIL or Tata Structura catalogues. If using Corner Radius mode with ri = 1.5t, results should match catalogue values within ±1%.
Standard formula vs corner radius formula — know when to use which
Treats corners as perfectly sharp right angles. Fast to apply by hand, used for quick estimates. Slightly overestimates cross-section area — typically 3–8% more than actual for standard IS 4923 sections.
Removes excess corner area based on actual inner radius (ri) and outer radius (ro = ri+t). Matches manufacturer catalogues. Recommended for procurement, structural BOQ, and foundation load calculations.
H×B = full outer rectangle. (H−2t)(B−2t) = inner void rectangle. Their difference = the hollow section wall area. This is a simple subtraction but treats each corner as a complete 90° square, overestimating the corner material that is actually rounded away in production.
At each of the 4 corners, the real material forms a quarter-annulus (quarter ring) between ri and ro. The "square corner" excess area removed is (4−π)(ro²−ri²) = (4−π)·t·(2ri+t). For t=4mm, ri=6mm: correction = 0.8584 × 4 × (12+4) = 54.94 mm² per section.
Area in mm² × density in g/cm³ ÷ 1000 gives kg/m. The ÷1000 combines the mm²→cm² conversion (÷100) and the length unit (×1000mm per metre) and g→kg (÷1000) into one clean divisor. Verified against IS 4923:1997 section tables.
For IS 4923 carbon steel (7.85 g/cm³), a quick field check: kg/m = A(mm²) × 0.00785. Alternatively, the old approximation kg/m = 0.0157 × t × (H + B − 2t) works for sharp-corner estimates within ±4%.
Common Rectangular Hollow Sections — carbon steel, density 7.85 g/cm³, ri = 1.5t (corner radius formula)
| Section H×B (mm) | Thickness t (mm) | ri (mm) | Area – Std (mm²) | Area – CR (mm²) | kg/m (Std) | kg/m (CR) | 6 m Piece (CR) |
|---|---|---|---|---|---|---|---|
| RHS 40×20 | 2 | 3.0 | 224 | 210 | 1.76 | 1.65 | 9.90 |
| RHS 50×25 | 2.5 | 3.75 | 350 | 329 | 2.75 | 2.58 | 15.50 |
| RHS 60×30 | 2.5 | 3.75 | 425 | 404 | 3.34 | 3.17 | 19.02 |
| RHS 60×40 | 3 | 4.5 | 564 | 533 | 4.43 | 4.18 | 25.10 |
| RHS 75×50 | 4 | 6.0 | 936 | 881 | 7.35 | 6.92 | 41.50 |
| RHS 80×40 | 3 | 4.5 | 684 | 653 | 5.37 | 5.13 | 30.75 |
| RHS 80×40 | 4 | 6.0 | 896 | 841 | 7.03 | 6.60 | 39.62 |
| RHS 80×60 | 4 | 6.0 | 1056 | 1001 | 8.29 | 7.86 | 47.16 |
| RHS 100×50 | 3 | 4.5 | 864 | 833 | 6.78 | 6.54 | 39.24 |
| RHS 100×50 | 4 | 6.0 | 1136 | 1081 | 8.92 | 8.49 | 50.92 |
| RHS 100×50 | 5 | 7.5 | 1400 | 1314 | 10.99 | 10.32 | 61.89 |
| RHS 100×60 | 4 | 6.0 | 1216 | 1161 | 9.55 | 9.11 | 54.67 |
| RHS 120×60 | 4 | 6.0 | 1376 | 1321 | 10.80 | 10.37 | 62.22 |
| RHS 120×60 | 5 | 7.5 | 1700 | 1614 | 13.35 | 12.67 | 76.02 |
| RHS 120×80 | 5 | 7.5 | 1900 | 1814 | 14.92 | 14.24 | 85.44 |
| RHS 150×75 | 5 | 7.5 | 2150 | 2064 | 16.88 | 16.20 | 97.20 |
| RHS 150×100 | 6 | 9.0 | 2856 | 2732 | 22.42 | 21.45 | 128.70 |
| RHS 200×100 | 6 | 9.0 | 3456 | 3332 | 27.13 | 26.16 | 156.96 |
| RHS 200×100 | 8 | 12.0 | 4544 | 4324 | 35.67 | 33.94 | 203.64 |
| RHS 250×150 | 8 | 12.0 | 6144 | 5924 | 48.23 | 46.50 | 279.00 |
| RHS 300×150 | 10 | 15.0 | 8800 | 8466 | 69.08 | 66.46 | 398.76 |
* Std = Standard sharp-corner formula | CR = Corner Radius formula (ri = 1.5t) | Carbon steel 7.85 g/cm³ | Per IS 4923:1997. For BIS certified values visit Bureau of Indian Standards. Actual values may vary within IS 4923 mass tolerance of ±6%.
Density values used to calculate hollow section weight across different materials
Density values are mean engineering references. For alloy-specific values, refer to the Material Test Certificate (MTC). Critical applications require density verification from certified laboratory reports.
Primary applications driving demand for Rectangular Hollow Sections across Indian construction in 2026
RHS sections form purlins, girts, wind columns, and mezzanine beams in PEB structures across India's industrial corridors — from Delhi NCR to Pune and Coimbatore. Weight accuracy directly impacts foundation and anchor bolt design.
NHAI and state highway projects use RHS for overhead sign gantries, crash barriers, guard rail posts, and toll booth canopy frames. SAIL and Tata sections with IS 4923 certification are mandatory under MoRTH specifications.
100×50 and 120×60 RHS are the backbone of large solar farm tracker and fixed-tilt mounting systems. With India targeting 500 GW renewable capacity by 2030, RHS demand for solar structures is growing rapidly in 2026.
Architects specify RHS beams and columns for commercial buildings, IT parks, and metro station structures. IS 800:2007 structural design requires precise dead load — making accurate RHS weight calculation essential.
Machine bases, conveyor frames, process equipment skids, and storage rack uprights across Indian manufacturing plants use RHS sections. Procurement teams calculate total tonnage using weight tables for vendor quotations.
Civil estimators preparing Bill of Quantities for steel tenders convert RHS drawing dimensions to total kg per item. Accurate weight — not approximate — is critical to avoid under-bidding or material shortfalls on site.
Field-tested advice from structural engineers and steel fabricators across India
Mill Test Certificates (MTC) list measured actual dimensions. IS 4923 allows ±1 mm on H and B and ±10% on wall thickness. For large orders, weigh a sample piece and back-calculate density — unexpected thin walls are a common QC issue with Indian secondary market steel.
For quick site estimates, the Standard formula is fine. For a structural BOQ, foundation load schedule, or purchase order involving more than 10 tonnes, always use the Corner Radius formula. The 4–8% difference on a 50-tonne project equals 2–4 tonnes of steel — significant at current Indian market rates of ₹65,000–75,000 per tonne in 2026.
IS 4923:1997 Clause 10 allows ±6% mass tolerance per piece and ±4% per consignment. Add 5% to your calculated order quantity to ensure you receive at least the design tonnage. Underfill after cutting is a common site problem, especially with consignments from secondary steel dealers.
Hot-dip galvanising adds approximately 500–600 g/m² of zinc, which is about 0.3–0.8 kg/m on a 100×50×4 RHS. Epoxy primer + finish adds roughly 0.2–0.4 kg/m. For coastal projects in Mumbai, Chennai, or Visakhapatnam, heavy-duty coating weight should be included in dead load calculations. See our Pipe Weight Calculator for a similar coating allowance approach.
Add 3–5% wastage for mitre cuts, coping, notching, and end preparation. For portal frame fabrication with many complex connections, 5–8% cut allowance is realistic. Base your purchase order on gross weight including all wastage — this is what you pay for at the steel service centre.
Both ERW (Electric Resistance Welded) and SAW (Submerged Arc Welded) RHS sections use the same weight formula. ERW is the most common IS 4923 product in India. For sections above 200×200, SAW fabricated sections are sometimes used — verify the wall thickness from the drawing, as SAW sections may be thicker at the weld seam.
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Common questions about RHS weight calculation answered for Indian engineers and fabricators