Structural steel weight calculator for I-beams, channels, angles and flats
This structural steel weight calculator gives the weight per metre and the total weight of rolled steel sections: ISMB I-beams, ISMC channels, ISA equal angles and MS flats, plus US W-shapes. Pick a section from the IS 808 tables or enter your own dimensions, set the length and number of pieces, and it shows kg per metre, the weight of one piece, the total in kg, tonnes and pounds, and the cost at your price per kg or tonne.
Under the calculator is a weight chart for the chosen family — the familiar MS channel weight chart, ISMB chart, angle chart or MS flat chart — with kg per metre and the weight of a 6 m and a 12 m length, and your section highlighted.
It is for estimating, ordering and checking weighbridge slips. Rolled sections vary within the tolerances of IS 1852, so billing uses the actual weight; the structural design itself must come from a qualified engineer.
How to use the Structural Steel Weight Calculator
- Choose I-beam, Channel, Angle or Flat, and metric or imperial units.
- Pick the table — IS 808:1964 (ISMB / ISMC), IS 808:1989 (MB / MC), IS 808 equal angles, an AISC W-shape, or custom dimensions — and the section size.
- For custom sections or flats, enter the depth, flange width and thicknesses (or legs and thickness), and the density if it is not mild steel.
- Enter the length of each piece, the number of pieces and the price per kg, tonne, lb or US ton.
- Read the kg per metre, piece weight, total and cost; copy the summary or use the chart below.
Structural Steel Weight Calculator features
IS 808 section tables
ISMB 100–600 and ISMC 75–400 from IS 808:1964 (SP 6(1)), MB and MC from the 1989 revision, and 72 equal angles from IS 808:1989 Table 5.1.
Any size from dimensions
Custom I-sections, channels, equal or unequal angles and flats are computed as area × 7,850 kg/m³, with the formula shown.
US W-shapes
A W-shape designation carries its nominal weight: W12x26 is 26 lb/ft (38.69 kg/m). Type any designation.
Weight charts
kg/m, kg per 6 m and kg per 12 m for the whole family, with the chosen size highlighted.
How steel section weight is calculated
Weight per metre = cross-section area × density. Steel is 7,850 kg/m³, which is 0.00785 kg per mm² per metre, so a section of 1 cm² weighs 0.785 kg/m — the factor IS 808 itself uses between its area and mass columns.
An MS flat 50 × 6 mm has an area of 300 mm² and weighs 300 × 0.00785 = 2.355 kg/m, or 14.13 kg for a 6 m length. An equal angle 50 × 50 × 6 mm has an area of about t(A + B − t) = 6 × 94 = 564 mm², giving 4.43 kg/m; the IS 808 table lists 4.5 kg/m because the rolled root fillet adds a little steel. An I-beam such as ISMB 200 (200 × 100 mm, 5.7 mm web, 10.8 mm flange) works out at 24.94 kg/m from the rectangles alone against 25.4 kg/m in the table, for the same reason — so the table value is the one to use for a standard section.
| Section | kg/m | kg per 6 m | Source |
|---|---|---|---|
| ISMB 150 · 200 · 300 | 14.9 · 25.4 · 44.2 | 89.4 · 152.4 · 265.2 | IS 808:1964 (SP 6(1)) |
| ISMC 75 · 100 · 150 | 6.8 · 9.2 · 16.4 | 40.8 · 55.2 · 98.4 | IS 808:1964 (SP 6(1)) |
| ISA 40×40×5 · 50×50×6 · 75×75×6 | 3.0 · 4.5 · 6.8 | 18.0 · 27.0 · 40.8 | IS 808:1989 |
| Flat 25×5 · 50×6 · 75×10 | 0.981 · 2.355 · 5.888 | 5.9 · 14.1 · 35.3 | computed |
ISMB or MB? The two IS 808 tables
IS 808 was revised in 1989 and some medium-weight beams and channels changed shape: MB 200 is 24.2 kg/m against 25.4 kg/m for ISMB 200, and MB 100 is 100 × 50 mm and 8.9 kg/m against 100 × 75 mm and 11.5 kg/m for ISMB 100. Most mills and dealers still sell and chart the ISMB/ISMC sizes, so they are the default here; switch the table if your drawings say MB or MC. Three scanned masses (MB 450, ISA 35×35×4 and ISA 75×75×10) were unreadable and are taken as 0.785 × the tabulated area.
For reinforcement bars use the steel weight calculator; for beam bending and deflection the beam calculator.
Structural Steel Weight Calculator FAQ
What is the weight of ISMB 200 per metre?
ISMB 200 weighs 25.4 kg/m (IS 808:1964 / SP 6(1)), so a 6 m length is 152.4 kg. The 1989 MB 200 section is 24.2 kg/m.
What is the weight of an MS angle 50 × 50 × 6?
IS 808:1989 lists ISA 50 × 50 × 6 at 4.5 kg/m, about 27 kg for a 6 m length. The angle weight calculator also works out any other size from its legs and thickness.
How do I calculate MS channel weight?
Look up the section in the IS 808 table — ISMC 100 is 9.2 kg/m, ISMC 150 16.4 kg/m — and multiply by the length. For a non-standard channel, enter the depth, flange width and thicknesses.
What is the formula for MS flat weight?
Weight in kg/m = width (mm) × thickness (mm) × 0.00785. A 50 × 6 mm flat is 2.355 kg/m.
How much does a W12x26 beam weigh?
The number after the x is the nominal weight: 26 lb per foot, 38.69 kg/m. A 20 ft beam weighs 520 lb (236 kg).
Why does my supplier’s weight differ?
Rolled sections are made within mass tolerances (IS 1852 in India), and dealers may quote the 1964 or 1989 table. The weighbridge weight is what is billed.