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Calcimator

Shelving Load Calculator

Calculate maximum safe weight for shelves by material, thickness, span, and bracket spacing. Includes deflection estimate.

Inputs

in
in
in
in

Results

Safe Working Load

22 lbs

≈ 5 bags of sugar

Brackets Needed

2 brackets

Maximum Load37 lbs
Deflection at Safe Load0.01 in
Safe Load per Foot7.3 lbs/ft
How to Use This Calculator
  1. Enter Shelf Length, Shelf Depth, and Shelf Thickness.
  2. Set Shelf Material and Bracket Spacing.
  3. Review Safe Working Load (lbs) and Brackets Needed (brackets).
  4. Use Maximum Load (lbs) and Deflection at Safe Load (in) to inform your decision.

How the result changes with Shelf Thickness

Shelf ThicknessSafe Working LoadBrackets Needed
0.5311 lbs2 brackets
1.2158 lbs2 brackets
2.04166 lbs2 brackets
2.73297 lbs2 brackets

What each input means

Shelf Length
Total shelf length from end to end.
Shelf Depth
Front-to-back depth of the shelf board.
Shelf Thickness
Thickness of the shelf board (standard is 3/4").
Shelf Material
0 = pine, 1 = oak, 2 = plywood, 3 = MDF, 4 = tempered glass.
Bracket Spacing
Distance between brackets/supports. Shorter spacing = higher load capacity.

What each result means

Safe Working Load
Recommended maximum load with a 5x safety factor.
Maximum Load
Absolute maximum load (3x safety factor — not recommended for daily use).
Deflection at Safe Load
Expected sag at center of span under safe working load.
Brackets Needed
Number of bracket supports for the specified spacing.
Safe Load per Foot
Distributed safe weight capacity per linear foot of shelf.

How this is calculated

Worked example, using the default values

  1. Identify Input Parameters
    4 parameters
    Shelf Length = 36, Shelf Depth = 10, Shelf Thickness = 0.75, Shelf Material = 0 = 5 input(s) provided
  2. Calculate Safe Working Load
    Safe Working Load = max(0
    22 = 22
  3. Calculate Brackets Needed
    Brackets Needed
    2 = 2
  4. Calculate Maximum Load
    Maximum Load = max(0
    37 = 37
  5. Calculate Deflection at Safe Load
    Deflection at Safe Load = max(0
    0.005 = 0.005

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