Beam Load Calculator

This beam load calculator works out the support reactions, the maximum shear force and the maximum bending moment for a simply supported beam, the starting point for checking whether a beam is strong enough for the load it carries. It handles the two most common cases together: a uniformly distributed load spread evenly along the span, such as the self-weight of a floor or the pressure of a roof, plus a single point load applied at the centre, such as a post or a piece of plant. Enter the span between the supports, the intensity of the distributed load in kilonewtons per metre and the size of the central point load in kilonewtons, and the calculator adds the loads, splits them equally between the two supports because the arrangement is symmetric, and returns the reaction at each end, the peak shear and the peak bending moment at midspan. The bending moment is the number designers care about most, because it drives the size and grade of timber, steel or concrete you need. This tool gives the load effects only: turning them into a member size also needs the material strength and the section properties, so treat the result as a first check and have any structural element confirmed by a chartered engineer.

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A 4 m simply supported beam carrying 5 kN/m plus a central 10 kN point load has 15 kN reactions at each support, a peak shear of 15 kN and a maximum bending moment of 20 kN·m at midspan.

Assumes a simply supported beam, a uniform load over the full span and a point load at the centre. Load effects only: sizing the beam also needs material strength and section properties. Have structural work confirmed by an engineer.