Calculate the Capacity of a Bookshelf or Bookcase
You can compute the capacity of a standard rectangular bookcase using simple arithmetic. All you need to know is the width of each shelf, the number of shelves, and the average width of a book in your collection. This is a useful calculation to make when you are in the home furnishings store or shopping for a book display case online.
First, measure the interior width across each shelf in inches or centimeters and multiply this distance by the number of rows. If you plan to pack two rows of books along a single shelf, increase the number of rows by the appropriate number. Call your final answer A.
Estimate the average width of a book in your collection, in inches or centimeters and call this number B. Then compute A/B. Make sure A and B are in the same units. Your answer is the approximate number of books your bookcase can hold.
You want to buy a bookcase that has 6 shelves, each of which is 83 cm across. You do not plan to stack any double rows of books, so the value of A is 6*83 = 498.
You also estimate that your average book width is 2.5 cm, so B = 2.5.
Finally, A/B = 498/2.5 = 199.2, so this bookcase can hold about 199 books.
At a garage sale you pick up a bookcase that has 4 tall shelves, each of which is 110 cm across. You plan to fill each shelf with a single row of thick binders, so your value of A is 4*110 = 440.
You estimate the average width of your binders is 6 cm, so B = 6.
To compute the capacity, you compute A/B. This gives you 440/6 = 73.33. Therefore, you can fit about 73 binders in the bookcase.