Beam Load Calculator
Max moment, shear, and midspan deflection for simply-supported beams under UDL or point load.
Formulas (simply-supported beam, midspan results)+
UDL (w over full span L): M = wL²/8 · V = wL/2 · δ = 5wL⁴/(384EI)
Point load P at midspan: M = PL/4 · V = P/2 · δ = PL³/(48EI)
Euler-Bernoulli beam theory, elastic range, fully braced compression flange.
First-pass sizing only. Final design must check LTB, web crippling, bearing, load combinations (LRFD/ASD), and serviceability per the governing code, sealed by a licensed Structural or Civil P.E.
Frequently asked questions
What kind of beam does this tool analyze?+
A simply-supported prismatic beam with either a uniformly distributed load (UDL) over the full span or a single concentrated point load at midspan. For continuous or fixed-end beams, hand the result to a structural engineer.
Are the deflection limits code-compliant?+
L/360 for live load and L/240 for total load are IBC default serviceability targets. Stricter limits (L/600 for masonry over beam, L/480 for plaster) apply in specific cases.
Does this account for self-weight, shear deformation, or lateral-torsional buckling?+
Self-weight: no — add it to your distributed load. Shear deformation: negligible for slender beams. LTB: no — assume the compression flange is fully braced (this tool is for first-pass sizing only).
What is E and I?+
E is Young's modulus (steel ≈ 29,000 ksi; concrete ≈ 4,000 ksi; SPF lumber ≈ 1,400 ksi). I is the moment of inertia of the section about the bending axis (look up in AISC, NDS, or ACI tables).
Can I use SI units?+
Yes — toggle the unit system and inputs/outputs switch to mm, kN, kN·m, and kN/m consistently.
Why is my deflection so large?+
Either the span is too long, the section is too shallow (I too small), or the load is too high. Doubling depth typically cuts deflection by a factor of 8.