Shelf Deflection Calculator
Shelf deflection depends on span, thickness, depth, load, material stiffness and support condition. The working shelf sag calculator compares deflection with an L/n limit and reports bending stress.
shelf deflection calculator shelf sag calculator floating shelf deflection
Rectangular shelf inertia
I = depth * thickness^3 / 12
Uniform-load sag
delta = 5 * W * L^3 / (384 * E * I)
Material caution
Plywood, MDF, particleboard and solid wood differ by grade, grain direction, moisture and long-term creep. Use manufacturer data for important shelves.
Related pages
- Shelf sag calculator - live shelf deflection and bending-stress screen.
- Plywood sheet calculator - sheet-good takeoff after sizing shelves.
- Cut list calculator - turn shelf dimensions into stock cuts.
- Beam deflection calculator - general beam formulas for comparison.