Structural Steel Quantity Calculator

Work out structural steel quantity instantly with clear inputs, formula shown and shareable results.

About Structural Steel Quantity Calculator

Structural steel is bought and priced by weight, so quantity is member length times the section's kilograms per metre times the number of members. A five to ten percent allowance covers cutting waste, cleats, stiffeners, base plates and bolts that are not in the member schedule.

Formulas

Steel weight

kg = length x kg per metre x number of members

Order weight

Tonnes = net kg x (1 + allowance) / 1000

Worked example

With the default values below, Structural Steel Quantity Calculator returns Steel to order of 6.910. Change any input above and every figure here is recalculated in your browser.

Inputs used

Length per memberminimum 0.1 m: 6 m
Section weightminimum 0.1 kg/m: 45.7 kg/m
Number of membersminimum 1: 24
Wastage and connections allowanceaccepts 0–30 %: 5 %

Results

Steel to order: 6.910 t
Net member weight: 6,580.8 kg
Wastage and connection allowance: 329.0 kg
Weight per member: 274.20 kg

Step by step

1Values used
2Steel weight
3Order weight
4Steel to order= 6.910 t
5Net member weight= 6,580.8 kg
6Wastage and connection allowance= 329.0 kg
7Weight per member= 274.20 kg

Assumptions and limits

The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 3 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

How is the Structural Steel Quantity figure worked out?

kg = length x kg per metre x number of members. Structural steel is bought and priced by weight, so quantity is member length times the section's kilograms per metre times the number of members.

Should connections be measured separately?

On a detailed take-off yes, because fabricated connections can add 8-12 percent on a braced frame. The percentage allowance here is for early estimating.

What values do I need to enter?

This calculator takes 4 inputs: Length per member, Section weight, Number of members, Wastage and connections allowance. The pre-filled defaults are a realistic worked example — replace them with your own site or project figures.