I have a shelf that is about 4 feet long 2 feet wide and 1 1/2 inch thick. I would like to place an item on it that weighs about 90 pounds. I want to know if it will hold that and I don't know how to calculate it.

  • 1
    What is the shelf made of , how is it anchored to the wall or supported from the floor. Much more information will be needed.
    – Ed Beal
    Mar 4 '20 at 0:11
  • 1
    Assuming proper support at the ends, I'd happily stand on that shelf if made of a normal wood species, (not balsa) and I weigh a lot more than 90 lbs....
    – Ecnerwal
    Mar 4 '20 at 1:06
  • A 1 1/2 inch thick shelf will laugh at 90 pounds all day every day. Your real concern is whether the shelf itself is properly anchored to support 90 pounds. A picture would be nice.
    – MonkeyZeus
    Mar 4 '20 at 13:19
  • What type of wall will you be mounting this switch on?
    – JACK
    Mar 4 '20 at 13:31
  • We need to know what the shelf is made out of and how it's hung on the wall.
    – Phaelax z
    Mar 4 '20 at 16:04

There is a cool site for this: The "sagulator" for computing this. It's intended more for freespan shelves (like a book case), but you might be able to use it to answer your question. Hope it meets your needs. Ed makes a good point about support as well. With that weight it will need to be fastened to studs with multiple brackets.

Edit: Forgot the link, here it is: https://www.woodbin.com/calcs/sagulator/

  • The "I forgot the attachment" of the forum world? lol Mar 4 '20 at 22:04

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