Beam Load Calculator
Calculate the maximum safe center point load a simply-supported rectangular beam can carry, based on its span, dimensions and allowable bending stress.
About the Beam Load Calculator
This calculator gives a simplified estimate of the maximum center point load a simply-supported rectangular beam can safely carry before exceeding its material's allowable bending stress — a strength check, complementing the Beam Deflection Calculator's serviceability (sag) check.
Formula: Section Modulus (S) = (Width × Depth²) ÷ 6; Maximum Moment = Allowable Bending Stress (Fb) × S; Maximum Safe Load (P) = (4 × Maximum Moment) ÷ Span (in inches), derived from the standard center-load moment equation M = PL ÷ 4.
The allowable bending stress values used here are rounded reference figures for common material grades, not official code design values — actual allowable stress depends on species, grade, load duration and other engineering adjustment factors. This result also doesn't check shear capacity or deflection limits, either of which can govern before the bending limit is reached. Always verify beam sizing against published span tables or a structural engineer's stamped design for any load-bearing application.