Section Properties Calculator — Area, Centroid, Inertia | BeamMetric

Calculate area, centroid, moment of inertia, and section modulus for I-beams, rectangles, channels, and custom sections.

How to Use the Moment of Inertia Tool

Select the section shape (I-beam, Rectangular, Circular, or Tube). Enter the required dimensions like flange width, web thickness, and height.

The calculator determines the Area Moment of Inertia (Ix and Iy). This value represents the shape's resistance to bending based on its geometry.

For I-beams, the majority of the bending resistance comes from the distance of the flanges from the neutral axis. This is why tall, thin beams are efficient.

FAQ

Why are I-beams shaped that way?

The 'I' shape puts the most material at the top and bottom (flanges), where the bending stress is highest, resulting in a high moment of inertia with minimal weight.

What is the difference between Ix and Iy?

Ix refers to bending resistance about the horizontal axis (usually the strong axis), while Iy refers to resistance about the vertical (weak) axis.

Can I calculate inertia for a hollow tube?

Yes. Our tool supports hollow rectangular and circular sections. The formula involves subtracting the inertia of the inner void from the outer dimension.

How much does inertia change if I rotate or deepen a section?

Inertia is intensely sensitive to depth because it scales with the cube of the dimension in the bending direction. Turning a 50×200 mm rectangle from flat to upright multiplies its moment of inertia by sixteen (2.08×10⁶ → 3.33×10⁷ mm⁴). Adding depth is always far more effective than adding width for resisting bending.