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Beam Bending Stress Calculator

Apply the flexure formula to common beam section shapes and custom section modulus values.

Beam Bending inputs

Result section

warningrectangular

Extreme-fiber bending stress

0.012 MPa

Secondary results

Bending moment: 1 N*m
Second moment of area: 4.16667e-6 m^4
Extreme-fiber distance: 0.05 m
Section modulus: 8.33333e-5 m^3
Section area: 0.005 m^2

Unit conversion summary

Unit-normalization summary: 12,000 Pa; 1 N*m; 8.33333e-5 m^3

Warnings

Calculations are performed locally in your browser and are not submitted to a third-party calculation API.
Positive normal stress is tension. Negative normal stress is compression. Positive shear follows the displayed stress-element convention.

Assumptions

Straight prismatic beam, linear elastic bending, small deflection, and selected section axis.
This does not check shear, deflection, buckling, local bearing, fatigue, or load combinations.

Calculation steps

Resolve section propertiesRectangular section about the centroidal bending axis
Calculate section modulus8.33333e-5 m^3
Calculate bending stress12,000 Pa

Beam flexure formula

sigma = M c / I = M / S

sigma = M c / I = M / S.

sigma = 1 N*m / 8.33333e-5 m^3

Technical visual

Engineering interpretation

Bending stress is reported at the selected extreme fiber using the flexure formula.

What is the beam bending stress calculator?

Use this calculator for simple prismatic-beam bending-stress checks when the bending moment and section axis are already known.

How to use the beam bending stress calculator

Select the mode that matches the stress, material, section, or thermal data you already have.
Enter values with units; the calculator normalizes inputs to SI internally.
Review the formulas, normalized values, assumptions, and warnings before transferring the result to another check.
Use the transfer link to send the calculated bending stress to the Factor of Safety Calculator when a uniaxial stress comparison is appropriate.

Input explanations

Rectangular sections use I = b h^3 / 12 about the centroidal bending axis.
Solid circular sections use I = pi d^4 / 64.
Hollow circular sections use I = pi (Do^4 - Di^4) / 64.
Custom mode accepts either section modulus directly or second moment of area plus extreme-fiber distance.

Notation

Formula notation
Symbol	Meaning	Unit
M	Bending moment	N*m
I	Second moment of area	m^4
c	Extreme-fiber distance from neutral axis	m
S	Section modulus	m^3
sigma	Bending stress	Pa

Worked examples

M = 1 N*m and a 50 mm by 100 mm rectangle gives stress about 0.012 MPa.

A custom section modulus can be entered directly when it is known from a section table.

The result is extreme-fiber bending stress only; deflection and buckling are not solved.

Cross-tool workflow

The Beam Bending Stress Calculator supports rectangular, solid circular, hollow circular, and custom section-property modes. It reports section modulus, second moment of area, and extreme-fiber bending stress.

Use stress in Factor of Safety Calculator

Common mistakes

Using the wrong bending axis for the entered section dimensions.
Entering diameter where radius or distance-to-fiber was expected.
Using this as a beam-deflection, shear, torsion, buckling, or fatigue calculator.
Forgetting stress concentration, lateral torsional buckling, local buckling, welds, or connection details.

Limitations

Only simple flexure stress is calculated.
Beam deflection, shear stress, torsion, buckling, fatigue, load combinations, and code checks are not included.
The result assumes a straight prismatic member and linear elastic stress distribution.

References

Roark's Formulas: Young, Budynas, and Sadegh, Roark's Formulas for Stress and Strain.
Shigley's Mechanical Engineering Design: Budynas and Nisbett, Shigley's Mechanical Engineering Design, McGraw-Hill.
Mechanics of Materials: Hibbeler, Mechanics of Materials, Pearson.
Theory of Elasticity: Timoshenko and Goodier, Theory of Elasticity, McGraw-Hill.

What formula does this beam calculator use?

It uses sigma = M c / I, equivalently sigma = M / S.

Does it calculate beam deflection?

No. Deflection is outside Phase 6.

Can I enter a custom section modulus?

Yes. Custom mode can use section modulus directly.

Does it check buckling?

No. Buckling, lateral torsional buckling, and local buckling are not included.

Which section axis is used?

The built-in formulas assume the displayed centroidal axis; verify the axis against your actual bending moment.

Does this calculator prove that a part is safe?

No. It reports an educational preliminary stress or factor comparison. Real design decisions need applicable standards, validated models, material data, and engineering review.

Can these results replace commercial FEA software?

No. ScholarTool provides transparent hand-calculation support and postprocessing checks, not a replacement for validated FEA solvers.

Professional support from ScholarEase Consultancy Services LLP

Professional FEA, simulation setup, solid-mechanics calculations, technical documentation, and research support are available through the connected services website. These calculators remain free to use without purchasing services.

Visit ScholarEase

Engineering disclaimer

This tool is intended for educational, estimation, and preliminary solid-mechanics support. Always verify critical engineering calculations with applicable standards, validated software, material data, and qualified professional judgment.

Need Professional Support?

ScholarTool is powered by ScholarEase Consultancy Services LLP. Professional engineering, simulation, research, and technical documentation support is available through the connected services website.

Visit ScholarEase

Last reviewed: 2026-06-21

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Beam Bending inputs

Result section

warningrectangular

Extreme-fiber bending stress

0.012 MPa

Secondary results

Bending moment: 1 N*m
Second moment of area: 4.16667e-6 m^4
Extreme-fiber distance: 0.05 m
Section modulus: 8.33333e-5 m^3
Section area: 0.005 m^2

Unit conversion summary

Unit-normalization summary: 12,000 Pa; 1 N*m; 8.33333e-5 m^3

Warnings

Calculations are performed locally in your browser and are not submitted to a third-party calculation API.
Positive normal stress is tension. Negative normal stress is compression. Positive shear follows the displayed stress-element convention.

Assumptions

Straight prismatic beam, linear elastic bending, small deflection, and selected section axis.
This does not check shear, deflection, buckling, local bearing, fatigue, or load combinations.

Calculation steps

Resolve section propertiesRectangular section about the centroidal bending axis
Calculate section modulus8.33333e-5 m^3
Calculate bending stress12,000 Pa

Beam flexure formula

sigma = M c / I = M / S

sigma = M c / I = M / S.

sigma = 1 N*m / 8.33333e-5 m^3

How to use the beam bending stress calculator

Select the mode that matches the stress, material, section, or thermal data you already have.
Enter values with units; the calculator normalizes inputs to SI internally.
Review the formulas, normalized values, assumptions, and warnings before transferring the result to another check.
Use the transfer link to send the calculated bending stress to the Factor of Safety Calculator when a uniaxial stress comparison is appropriate.

Symbol

Meaning

Unit

Bending moment

N*m

Second moment of area

m^4

Extreme-fiber distance from neutral axis

Section modulus

m^3

sigma

Bending stress

Common mistakes

Using the wrong bending axis for the entered section dimensions.

Entering diameter where radius or distance-to-fiber was expected.

Using this as a beam-deflection, shear, torsion, buckling, or fatigue calculator.

Forgetting stress concentration, lateral torsional buckling, local buckling, welds, or connection details.

References

Roark's Formulas: Young, Budynas, and Sadegh, Roark's Formulas for Stress and Strain.

Shigley's Mechanical Engineering Design: Budynas and Nisbett, Shigley's Mechanical Engineering Design, McGraw-Hill.

Mechanics of Materials: Hibbeler, Mechanics of Materials, Pearson.

Theory of Elasticity: Timoshenko and Goodier, Theory of Elasticity, McGraw-Hill.

Beam Bending inputs

Beam section

Result section

Secondary results

Unit conversion summary

Warnings

Assumptions

Calculation steps

Beam flexure formula

Technical visual

Engineering interpretation

What is the beam bending stress calculator?

How to use the beam bending stress calculator

Input explanations

Notation

Worked examples

Cross-tool workflow

Common mistakes

Limitations

References

Related tools

Professional support from ScholarEase Consultancy Services LLP

Print summary

Engineering disclaimer

Need Professional Support?

Beam Bending inputs

Beam section

Result section

Secondary results

Unit conversion summary

Warnings

Assumptions

Calculation steps

Beam flexure formula

Technical visual

Engineering interpretation

What is the beam bending stress calculator?

How to use the beam bending stress calculator

Input explanations

Notation

Worked examples

Cross-tool workflow

Common mistakes

Limitations

References

Related tools

Professional support from ScholarEase Consultancy Services LLP

Print summary

Engineering disclaimer

Need Professional Support?