Beam Load Calculator
Reactions, max moment, and optional deflection for a simply supported beam.
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Tool
Unit system
Switching resets the fields below to that system's typical units.
Beam and load
Simply supported beam with a single point load at midspan.
Deflection (optional)
Provide both modulus of elasticity and moment of inertia to estimate max deflection. Leave both blank to skip.
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About the beam load calculator
Estimate the support reactions, maximum bending moment, and (optionally) maximum deflection for a simply supported beam carrying a single point load at midspan — a common textbook and preliminary-design case.
Formulas used
Reactions: R = P/2 at each support. Max moment: M = PL/4 at midspan. Max deflection (if E and I are provided): δ = PL³/(48EI), also at midspan.
Assumptions — please read
Pin-and-roller (simply supported) end conditions. A single point load exactly at midspan. Linear-elastic, homogeneous, isotropic material. Small-deflection (Euler-Bernoulli) beam theory, which neglects shear deformation. The beam's own self-weight is excluded unless you add it to the point load.
Not covered
Distributed loads, multiple or off-center point loads, cantilever or fixed-end conditions, lateral-torsional buckling, shear stress, and code-specific safety factors are all out of scope. This tool is for quick estimates and learning — not a replacement for a licensed structural engineer or a code- compliant analysis (AISC, Eurocode, etc.) on real projects.
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FAQ
Quick answers to common questions.