Steel beam calculator
Pick a W-shape, set your span and loads, and read instant reactions, shear/moment diagrams, deflection curves and stress checks. Toggle self-weight, switch metric/imperial units, export CSV or print a report.
About this case
How to use this steel beam calculator
Start with the pre-loaded simply supported beam, then set your real span between supports. Replace the uniform load with your own line load in kN/m (multiply your floor or roof area load in kN/m² by the tributary width), or swap it for point loads at the exact positions where other beams or columns bear on this one.
Open the section library and pick a W-shape from the AISC list: W4 through W24 sections carry their real area and moment of inertia, so the deflection and bending stress results match published steel properties. The material preset uses structural steel with E = 200 GPa and fy = 250 MPa; switch to a custom modulus only if you are working with a different alloy.
Reading the results for a steel design check
For a quick strength check, compare the reported maximum bending stress against the yield strength divided by your safety factor; a common allowable-stress approach keeps the working stress under roughly 0.6 × fy. For serviceability, watch the deflection badges: L/360 keeps brittle finishes safe on floors, and L/240 is the common roof limit.
If the beam fails serviceability but passes strength, choose a deeper W-shape: deflection scales with 1/I, and deeper sections gain moment of inertia much faster than weight. Export the CSV or print the report to attach a record of the load case to your calc package.
Common steel beam mistakes this tool helps you catch
Forgetting self-weight is the classic error; toggle self-weight on and the section's mass becomes a uniform load automatically. Another is underestimating tributary width, which matters more than the area load itself. And when a steel beam sits over three or more posts, it must be modelled as continuous rather than as a series of simply supported spans: the hogging moment over the middle support changes the design.