Rectangular hollow section properties calculator for cross section area, weight, second moment of area, section modulus and radius of gyration calculation of  a hollow rectangular section.

Sectional properties of hollow rectangle
Parameter Value
Height [H]
Width [B]
Internal height [h]
Internal width [b]
Length [L]
Density [p]

Parameter Value
Cross section area (A) ---
Mass (M) ---
Second moment of area (Ixx) ---
Second moment of area (Iyy) ---
Section modulus (Sxx) ---
Section modulus (Syy) ---
Radius of gyration (rx) ---
Radius of gyration (ry) ---
CoG distance in x direction (xcog) ---
CoG distance in y direction (ycog) ---

Note: Use dot "." as decimal separator.



Radius of Gyration (Area): The capacity of a cross-section to resist bending.

Second Moment of 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.


Hollow Rectangle Formulas:

Sectional properties of hollow rectangle
Parameter Symbol Equation
Cross section area A A = BH-bh
Area moment of inertia Ixx Ixx = BH3/12 - bh3/12
Area moment of inertia Iyy Iyy = HB3/12 - hb3/12
Section modulus Sxx Sxx = Ixx/ycog
Section modulus Syy Syy = Iyy/xcog
Centroid xc xc=B/2
Centroid yc yc=H/2
Mass M M = ALρ
Radius of gyration r r = (I/A)^0.5


  • Oberg, E. , Jones ,F.D. , Horton H.L. , Ryffel H.H., (2016) . Machinery's Handbook . 30th edition.  Industrial Press Inc.
  • Oberg, E. , Jones ,F.D. , Horton H.L. , Ryffel H.H., (2012) . Machinery's Handbook . 29th edition.  Industrial Press Inc.