Free Online Beam Calculator

1. Set the beam length — enter the span in metres. Supports are automatically placed at each end.
2. Add loads — add point loads (kN at a position) or distributed loads (kN/m over a range). Mix and match as needed.
3. Click Calculate — see support reactions, shear force diagram, and bending moment diagram instantly.

Same Interface, Same Workflow

This calculator uses the same panel layout as the BeamBuddy Excel add-in. The input fields, section labels, result outputs, and diagram styles are all identical — so when you install the add-in, you'll already know how it works. The only difference is that the full add-in reads from and writes to your Excel cells.

Simply Supported Beam Analysis

A simply supported beam has a pin support at one end and a roller support at the other. This is one of the most common structural configurations in steel and concrete design. The pin support resists both vertical and horizontal forces, while the roller resists only vertical forces, allowing thermal expansion.

For a single point load P at distance a from the left support on a beam of span L, the reactions are: R₁ = P(L−a)/L and R₂ = Pa/L. The maximum bending moment occurs at the load point and equals R₁ × a.

When to Use the Full Add-in

This calculator handles simply supported beams with point and distributed loads. For continuous beams, trapezoidal loads, multiple spans, steel section selection from the Blue Book (BS EN 10365), Eurocode 3 design checks, or live Excel cell linking — install the full BeamBuddy Excel add-in. It includes 397 steel sections, supports up to 10 spans, and writes results directly into your spreadsheet.