Engineering

Beam Deflection Calculator

Estimate max deflection for a simply-supported beam with center load.

Last validated: 2026-02-14

Beam Deflection Calculator estimates maximum bending deflection for common support and loading cases. Beam deflection depends on load, span length, elastic modulus, and second moment of area. Elastic modulus describes material stiffness, while the second moment of area describes how strongly the cross-section resists bending; a deeper beam can be much stiffer even with the same material. Support conditions such as simply supported or cantilevered change the shape and magnitude of deflection, and point loads behave differently from distributed loads. This calculator is useful for mechanics education and preliminary design screening, but structural work should also check stress, buckling, connections, serviceability limits, load combinations, and applicable codes.

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Input Pattern

Enter values in the left panel, keep units explicit, run the calculation, then copy or share the result. Invalid fields are highlighted immediately.

Beam Deflection Inputs

Simply supported beam with center point load: delta = PL^3/(48EI)

Result

Max deflection: 0.0001041667 m

How to use this tool

Enter Load P (N), Span L (m), Elastic modulus E (Pa), Second moment I (m^4) for the beam deflection calculator, keeping units, dates, or text format consistent with the form labels.
Confirm all units and known variables before running the calculation so the formula is applied consistently.
Click "Run the tool" and review Beam Deflection Inputs, Result for the primary output.
Verify units and assumptions, especially before using the result for design, lab, or safety-sensitive work.

Worked Example

Auto-generated from the tool's current default or entered inputs.

Example Inputs

Load n: 1000.0
Span m: 2.0
Elastic modulus pa: 200000000000.0
Second moment m4: 8.0e-06

Expected Outputs

Load n: 1000
Span m: 2
Elastic modulus pa: 200000000000
Second moment m4: 0.000008

Interpretation

Load n is 1000.0. Use this as a decision input, not as a standalone conclusion.
Span m is 2.0. Use this as a decision input, not as a standalone conclusion.
Elastic modulus pa is 200000000000.0. Use this as a decision input, not as a standalone conclusion.
Confirm unit consistency and operational constraints before applying this result in production or field conditions.

Confidence and limitations

Outputs are deterministic formula results and depend entirely on input quality and units.
Results are for planning and learning; verify with domain standards before safety-critical use.
Use as a quick estimate only; validate against codes, tolerances, and project constraints.

Formula References

First-order engineering design formulas and unit conversions.
Results are quick estimates, not code-compliance validation.

Assumptions

Outputs are deterministic formula results and depend entirely on input quality and units.
Results are for planning and learning; verify with domain standards before safety-critical use.
Use as a quick estimate only; validate against codes, tolerances, and project constraints.

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Structural analysis resources

Recommend structural design software and engineering handbooks.

Beam Deflection Calculator

Input Pattern

Beam Deflection Inputs

Result

How to use this tool

Worked Example

Example Inputs

Expected Outputs

Interpretation

Confidence and limitations

Formula References

Assumptions

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