structural calculator
Simple Beam Calculator (Uniform Load)
Estimate the maximum bending moment and midspan deflection of a simply-supported beam under a uniform load.
How it works
Mmax = w L^2 / 8. Max deflection = 5 w L^4 / (384 E I). Keep all inputs in inch-pound units.
Worked example
120 in span, 100 lb/in, E=29,000,000 psi (steel), I=100 in^4: Mmax = 180,000 in-lb, deflection = 0.093 in.
When to use it
- Steel modulus of elasticity is about 29,000,000 psi.
- Keep every input in inch-pound units so the results stay consistent.
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All results are an engineering estimate — not for custody transfer. Field measurement and certified tables govern.