Shelf Deflection Calculator
Estimate center sag for a simply supported shelf under an evenly distributed load.
in
in
in
lb
psi
—Enter measurements to calculate
How the calculation works
Center deflection δ = 5wL⁴ ÷ (384EI), with I = bt³ ÷ 12 and w = W ÷ L.
Example
A 36×12×0.75-inch shelf with 40 lb and E=1.5M psi sags about 0.038 inch.
When to use this calculator
Use it to compare shelf thicknesses, spans, edging, and material stiffness.
Results are planning estimates. Verify critical dimensions, machine settings, material specifications, and local code requirements before work begins.
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