"American Standard Beam (S Shape) Sizes Calculator" has been developed to show basic dimensions and sectional properties of American standard beam (S shape). 

American standard beam is generally known as S beam or S shape. S shape is a rolled section with two parallel flanges connected by a web. S shapes have relatively narrow flanges. The designation of the S shape gives information about the width and weight per unit length. For example S12 X 50 means 12 inches depth and 50 pounds per foot weight per unit length.

The dimensions of the standard S shapes are defined in the annex of ASTM A 6/A 6M standard.



Nominal Depth Weight in pounds per foot


Structural Steel Shapes - W Shape
Parameter Symbol Value Unit
Designation --- --- ---
Weight per unit length W --- lb/ft
Cross section area A --- in^2
Depth d --- in
Web thickness tw ---
Flange width bf ---
Flange thickness tf ---
Second moment of area Ixx --- in^4
Second moment of area Iyy ---
Section modulus Sxx --- in^3
Section modulus Syy ---
Radius of gyration rx --- in
Radius of gyration ry ---

Note: Use dot "." as decimal separator.


Second Moment of Area: The capacity of a cross-section to resist bending.

Radius of Gyration (Area): The distance from an axis at which the area of a body may be assumed to be concentrated and the second moment area of this configuration equal to the second moment area of the actual body about the same axis.

Section Modulus: The moment of inertia of the area of the cross section of a structural member divided by the distance from the center of gravity to the farthest point of the section; a measure of the flexural strength of the beam.


  • Oberg, E., Jones, F. D., Horton, H. L., & Ryffel, H. H. (2012) . Machinery's Handbook . 29th edition.  Industrial Press Inc., pp 2594 - 2597
  • A 6/A 6M - 05a , Standard Specification for General Requirements for Rolled Structural Steel Bars, Plates, Shapes, and Sheet Piling