Steelwork Weight Calculator — Total Steel Tonnage Estimate

A standard allowance for connection plates, bolts, cleats, stiffeners, and base plates is 10-15% of the main steel weight. For simple structures with bolted connections, 10% is adequate. For complex fabrications with moment connections, haunches, or stiffeners, allow 15% or more. Your fabricator will provide exact figures from their shop drawings.

The weight per metre is the last number in a steel section designation. For example, 254x146x37 UB weighs 37 kg/m. The full section properties are published in the Tata Steel Blue Book (SCI P363) and the Steel Construction Institute tables, available free online at steelconstruction.info.

Total weight is needed for: (1) ordering steel from the stockholder, (2) planning crane lifts and erection sequence, (3) calculating transport requirements, (4) estimating costs (steelwork is priced per tonne for fabrication and erection), and (5) checking foundation loads. Under-estimating weight leads to budget overruns and crane hire problems.

As of early-to-mid 2026, structural steelwork fabricated and erected typically costs between £2,500 and £4,000 per tonne, depending on complexity. Material only (supply of UB/UC sections ex-works) is around £1,000-£1,300 per tonne — prices have firmed up since 2025 following producer increases and the Carbon Border Adjustment Mechanism (CBAM) introduced from January 2026, so the long-standing £800 lower bound is now out of date. Simple portal frames sit at the lower end of the fabricated band; complex multi-storey structures with moment connections are at the higher end. These figures are indicative and volatile — always get specific live quotes from fabricators and stockholders.

Yes, always include the self-weight of the steel members in your dead load calculations. For beams, the self-weight is typically 1-3% of the applied load and can usually be accommodated within design margins. For long-span or heavily loaded structures, the steel self-weight becomes more significant and must be explicitly included.