With this frame calculator you compute the bending moment diagram, the shear force diagram and the support reactions of any plane frame structure, directly in the browser — free of charge, without signing up and without installing anything. It covers statically determinate structures such as the classic simply supported beam or cantilever as well as statically indeterminate ones such as continuous beams or frames. Draw your structure by clicking, add point loads, moment loads and distributed loads, and watch the internal force diagrams and the deflected shape update immediately.

How the calculator works internally is explained in the theory section, with derivations, formulas and worked examples you can follow step by step.

What the calculator does

Any plane frame structure: simply supported beams, cantilevers, continuous beams, frames and trusses, whatever the degree of static indeterminacy.
Trusses can be analysed too, as a special case of a general frame structure in which every member end is connected by a hinge, so that only axial forces occur.
All release types, freely combined: moment release, axial release and shear release, at any member end.
All the usual supports: roller, pinned, fixed and spring supports. Prescribed displacements cover support settlement.
For each member you can enter the modulus of elasticity, the cross-sectional area and the second moment of area directly, or compute them from a rectangular cross-section.
Any load at any position: point loads, moment loads, and distributed loads with a linear or parabolic shape, which covers uniformly distributed, trapezoidal and triangular loads, including over part of a member.
Immediate results with extreme values: the axial force diagram, the shear force diagram and the bending moment diagram, plus the reaction forces and the deflected shape with the deflection at any point. The diagrams can be shown one at a time or together.
The degree of static indeterminacy from the counting criterion, computed as you build.

Who it is for

This calculator is aimed at civil engineering students who want to follow or check structural analysis exercises, and at anyone who needs a quick estimate for a simple structure. For code-compliant design or complex three-dimensional structures, professional analysis software remains the right tool — for understanding internal force diagrams and for a fast check calculation, this one is the direct and free way. Whether you are looking for a quick beam calculator for a simply supported beam or a cantilever, or for a Gerber beam or a multiply statically indeterminate portal frame, the same tool covers it; the analysis always uses the direct stiffness method.