Bending Stress Calculator

Your details

Choose the beam cross-section profile. Dimension inputs change to match.
Unit for all cross-section dimensions.
Full width of the rectangle.
Full height of the rectangle (bending axis is horizontal).
The internal bending moment at the cross-section being checked.
Max bending stress (σₘₐₓ)Well within mild steel range
13.3333

Maximum normal stress at the extreme fibre of the cross-section.

Moment of inertia (I)28,125,000
Extreme fibre distance (c)75
Section modulus (S = I / c)375,000
Stress unitMPa
I unitmm⁴
c unitmm
S unitmm³
13.3333 MPa
Low stress<200Near mild-steel yield200-250Above mild-steel yield250-350Above high-strength yield350+

Max bending stress is 13.3333 MPa.

  • The section modulus is 375000.0000 mm³. A larger section modulus means the cross-section resists bending more efficiently.
  • The moment of inertia about the bending axis is 28125000.0000 mm⁴. Material further from the neutral axis contributes disproportionately more to I.
  • The extreme fibre is 75.0000 mm from the neutral axis. Stress is highest at this distance and zero at the neutral axis.

Next stepCompare this result against your material yield strength with an appropriate safety factor (typically 1.5 to 2.5 for structural steel). For a full beam check, also evaluate shear stress and deflection.

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