Steel Beam Size Selector (ISMB)
Required section modulus from load & span, with the lightest ISMB suggested.
Pick from the table, then ALWAYS verify deflection (often governs past ~6 m) and lateral-torsional buckling if the compression flange is unbraced.
Formula
Steel Beam Size Selector (ISMB) is a free steel beam size for structural engineers, fabricators and site engineers โ instant, accurate and 100% client-side, with the governing formula and reference shown next to the result so the number can be defended, not just quoted.
About Steel Beam Size Selector (ISMB)
Required section modulus from load & span, with the lightest ISMB suggested. The calculation implements M = wLยฒ/8; S_req = M/ฯ_allow โ lightest rolled section โฅ S_req (IS 808 section tables; IS 800). Pick from the table, then ALWAYS verify deflection (often governs past ~6 m) and lateral-torsional buckling if the compression flange is unbraced.
How to use Steel Beam Size Selector (ISMB)
- 1Enter UDL (incl. self-weight) in kN/m.
- 2Enter Simple span in m.
- 3Enter Allowable bending stress in MPa.
- 4Read Design moment, Required S instantly โ no submit button needed.
- 5Need US units? Flip the SI/Imperial toggle and every field converts.
Why use Steel Beam Size Selector (ISMB)?
- โImplements the standard formula โ M = wLยฒ/8; S_req = M/ฯ_allow โ lightest rolled section โฅ S_req
- โReference cited on-page: IS 808 section tables; IS 800
- โOne-click SI โ Imperial toggle โ values convert in place, physics stays in SI
- โBuilt-in engineering verdict flags out-of-range results instantly
- โRuns entirely in your browser โ nothing uploaded, free forever
Frequently asked questions
What formula does the Steel Beam Size Selector (ISMB) use?+
It computes M = wLยฒ/8; S_req = M/ฯ_allow โ lightest rolled section โฅ S_req, per IS 808 section tables; IS 800. The formula is displayed under the result.
What should I keep in mind when using this calculator?+
Pick from the table, then ALWAYS verify deflection (often governs past ~6 m) and lateral-torsional buckling if the compression flange is unbraced.
Can I use this for real structural design?+
It implements the exact textbook/code formula cited below the result and is ideal for sizing, checking and learning. Final designs should be verified by a qualified engineer against the full code with all load cases.
Is the Steel Beam Size Selector (ISMB) free to use?+
Yes โ completely free, no sign-up, no limits. It runs client-side in your browser, so inputs stay private and results are instant even on slow connections.
Related Engineering tools
Reynolds Number Calculator
Compute Re from density, velocity, pipe diameter and viscosity โ with instant laminar/turbulent classification.
โ LiveLaminar vs Turbulent Flow Classifier
Classify hydraulic-oil or process-fluid flow regime from kinematic viscosity, line velocity and tube bore.
โ LiveBernoulli Equation Solver
Solve downstream pressure between two points from velocities, elevations and fluid density (ideal, lossless).
โ Live