Select a calculation, enter the relevant values, then select Calculate to find a resisting moment, required section modulus, required bending stress, or simplified material/geometry result.

Educational model only. Use verified material values and governing-code factors; these calculations do not establish structural safety.

Optional settings

Examples only; not approved material design values.

Related Calculators

Moment of Resistance Formula

The following formula is used to calculate the moment of resistance for a given section modulus and allowable stress.

M = S × σ

Variables:

  • M is the moment of resistance
  • S is the section modulus
  • σ is the allowable stress

To calculate the moment of resistance, multiply the section modulus by the allowable stress.

What is Moment of Resistance?

The moment of resistance is a measure of the capacity of a structural element to resist bending. It is the product of the section modulus and the allowable stress. This elastic expression uses a supplied allowable stress. Stability, other failure modes, detailing and governing-code checks must be evaluated separately before structural use.

How to Calculate Moment of Resistance?

The following steps outline how to calculate the moment of resistance.

  1. First, determine the section modulus (S) of the structural element.
  2. Next, determine the allowable stress (σ) for the material of the structural element.
  3. Finally, calculate the moment of resistance using the formula M = S * σ.
  4. After inserting the values and calculating the result, check your answer with the calculator above.

Example Problem : 

Use the following variables as an example problem to test your knowledge.

Section modulus (S) = 200 cm³

Allowable stress (σ) = 150 MPa

Moment of resistance = 200,000 mm³ × 150 N/mm² = 30,000,000 N·mm = 30 kN·m.