Beam Deflection Calculator – Powerful & Accurate Structural Tool

Beam Deflection Calculator (Max δ)

Choose a beam and load case, enter inputs with units, and calculate the maximum deflection.

Mode (beam & load)

Simply supported — Point load at midspan Simply supported — Uniform load w Simply supported — Point load at distance a Cantilever — End point load Cantilever — Uniform load w Cantilever — End moment M

Inputs

Span length L

Young’s modulus E

Tip: steel ≈ 200 GPa, concrete ≈ 25–35 GPa.

Area moment of inertia I

Point load P

Distance a (from left support)

Uniform load w

End moment M

Unit changes preserve the same physical quantity and recalculate from the stored source value.

Results

Maximum deflection δ_max

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Select a case and calculate to see the governing formula.

Location of δ_max

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Measured from the left support or fixed end.

Step-by-step derivation

Enter values and click Calculate to see the formula, SI substitutions, and result.

References

Euler–Bernoulli beam theory for small deflections: deflection varies inversely with E·I.
Standard closed-form max-deflection cases are used for simply supported and cantilever beams.
The off-center simply supported point-load case evaluates the valid stationary point to get the true maximum deflection.

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