How do I calculate the weight threshold for cabinet carcasses based on the dimensions, material (e.g., plywood, mdf), and material thickness?

Has someone already worked out a nice formula that I can use?

1 Answer 1


The sagulator will give deflection values for horizontal shelf spans using various materials and thicknesses.

Unless you are working with extremely heavy loads (more than the weight of a countertop with people dancing on it), 3/4" material for the (vertical) cabinet walls should be more than adequate. As you make the walls thinner, they will still remain surprisingly strong as long as your cabinet design prevents racking.

Even 1/2" particleboard, which is not known for its strength, should hold up well to vertical compression/buckling, as you may know if you've ever had to pack up books that were stored on a cheap particleboard bookcase.

  • Thanks for the link, I'll look it over. There were some good references at the bottom of the site. I wanted an answer to the question in general but in my case I was looking to see what the thinest plywood I could use for an aquarium stand. I wonder if I just need find the vertical compression/buckling of the material. and double it for the two sides. The back and front are going to be mostly open.
    – bryjohns
    Mar 27, 2015 at 19:56
  • 1
    If the back and front will be mostly open, make sure your cabinet is braced to prevent racking. Also look into column buckling critical loads.
    – Doresoom
    Mar 28, 2015 at 3:09
  • I was able to find this - bgstructuralengineering.com/BGSCM13/BGSCM006/BGSCM00602.htm - as I get time I'll explore more and see if I can come up with something.
    – bryjohns
    Apr 2, 2015 at 19:16

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