Use this engineering calculation for a transparent preliminary estimate or independent arithmetic check when geometry, materials, loads, operating conditions, and units are defined consistently.

Diameter Meters (m)

Required number input.

Centroidal second moment of area of a solid circular section about any in-plane diameter: πd⁴/64. The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

Second Moment Meters4 (m⁴)

The resulting second moment meters4 returned as a number.

• Stress, strain, section, and torsion equations assume stated geometry, loads, supports, material behavior, and small deformation. Stress concentrations, instability, fatigue, fracture, plasticity, residual stress, and code factors may govern.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Check assumptions against drawings, measurements, current material data, and the applicable design code. Apply required load combinations and safety factors, then obtain qualified review and testing for consequential designs.

• Moment Inertia Rectangle

  Centroidal second moment of area for a solid rectangle about the axis parallel to its width: bh³/12.

• Wire Cross Section

  Circular solid conductor cross-sectional area from measured diameter, excluding insulation.

• Flywheel Mass Inertia

  Mass moment of inertia of a uniform solid disk flywheel about its center axis: I=½mr².