Steel Section Weight Calculator Guide
Quick Answer: A steel section weight calculator determines the mass per unit length (kg/m or lb/ft) of structural profiles using the cross-sectional area and steel density (7,850 kg/m3). The formula is: Weight (kg/m) = Cross-sectional area (m2) x 7,850 (kg/m3) x 1 m. For standard profiles like HEA, HEB, IPE, UPN, and RSA, tabulated weights from EN standards are more accurate than manual calculations because they account for fillet radii and tapered flanges.
Weight Calculation Formulas by Section Type
| Section Type | Simplified Area Formula | Example |
|---|---|---|
| I-beam (IPE/HEA/HEB) | A = 2 x b x tf + (h - 2tf) x tw | IPE 200: 2(100x8.5) + (200-17)x5.6 = 2,724 mm2 |
| Channel (UPN) | A = 2 x b x tf + (h - 2tf) x tw | UPN 200: 2(75x11.5) + (200-23)x8.5 = 3,230 mm2 |
| Equal angle (RSA) | A = 2 x L x t - t2 | RSA 100x100x10: 2(100x10) - 100 = 1,900 mm2 |
| Rectangular hollow (RHS) | A = 2t x (h + b - 2t) | RHS 200x100x8: 16(200+100-16) = 4,544 mm2 |
| Circular hollow (CHS) | A = pi x t x (D - t) | CHS 168.3x8: pi x 8 x 160.3 = 4,027 mm2 |
| Round bar | A = pi x D2 / 4 | D=50mm: pi x 2500/4 = 1,963 mm2 |
| Flat bar | A = b x t | 200x10: 2,000 mm2 |
b = flange width, tf = flange thickness, h = height, tw = web thickness, t = thickness, L = leg length, D = outer diameter.
To convert area to weight: Weight (kg/m) = A (mm2) x 7,850 / 1,000,000.
Reference Weights for Common Profiles
| Profile | Tabulated Weight (kg/m) | Calculated Weight (kg/m) | Difference |
|---|---|---|---|
| IPE 200 | 22.4 | 21.4 | +4.7% |
| HEB 200 | 61.3 | 58.8 | +4.3% |
| UPN 200 | 25.3 | 25.4 | -0.4% |
| RSA 100x100x10 | 15.0 | 14.9 | +0.7% |
| HSS 168.3x8 | 31.6 | 31.6 | 0.0% |
The simplified formulas underestimate weights for I-beams and H-beams because they ignore fillet radii at the web-to-flange junctions. For HEA and HEB profiles, the fillet radius adds 3-5% to the cross-sectional area. Always use tabulated EN standard weights for procurement and structural calculations.
Calculation Steps
- Identify the profile type and look up its dimensions from the relevant standard (EN 10034 for I-beams, EN 10279 for channels, EN 10056 for angles).
- Calculate the cross-sectional area using the appropriate formula from the table above.
- Multiply by steel density (7,850 kg/m3) to get weight per meter.
- Multiply by total length to get the total weight for material take-off and procurement.
- Apply a tolerance factor of +3 to +5% for I-beams and H-beams to account for fillet radii.
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