Calculate maximum bending moment, bending moment at a selected section, beam reactions, bending stress, section modulus demand, and simplified moment capacity. Use this bending moment calculator for simply supported beams, cantilevers, joists, rafters, headers, deck beams, floor beams, and preliminary structural planning.
Support reactions:
The calculator uses static equilibrium to estimate left and right reactions for simply supported beam cases.
Maximum moment:
The calculator applies common beam formulas or samples key load locations to estimate the controlling bending moment.
Section moment:
The calculator estimates the bending moment at the selected section from the left reaction minus load effects to the left.
Bending stress:
The calculator converts moment to inch-pounds and divides by section modulus to estimate bending stress.
A bending moment calculator helps estimate beam bending demand before checking beam size, section modulus, allowable stress, or moment capacity.
It can help compare maximum moment, moment at a section, support reactions, bending stress, required section modulus, moment capacity, and simplified utilization.
Your result shows estimated left reaction, right reaction, maximum bending moment, moment at the selected section, total load, bending stress, moment capacity, required section modulus, and simplified bending utilization. These are preliminary planning estimates only.
Bending moment is the internal turning effect in a beam caused by loads and reactions. It is one of the main values used to check beam strength.
For a centered point load or full-span uniform load, maximum bending moment occurs at midspan. With uneven point loads, it usually occurs where shear changes sign.
Convert the bending moment to inch-pounds, then divide by section modulus in cubic inches. The result is bending stress in PSI.
No. This calculator estimates bending moment and simplified bending stress only. Final beam design should also check shear, deflection, bearing, lateral bracing, connections, load combinations, material properties, and local code requirements.