I am planning on building a bookcase and some previous attempts have resulted in shelves that are too deep for most books.

Is there a average depth that would work best? For example would a 9 inch deep shelf fit for most books and standard paper (8.5 x 11)?


I walked around my existing book collection with a tape measure and determined that 9.5" inches will work for a) paperbacks b) average size other books c) binders.


Another possible option would be to query the Library of Congress (via API?) to see what the average/median dimensions are for books in the past 30 years.


I went with a 9.5 inch deep bookcase. This works well for most of my books and optimizes the usage of the 4'x8' sheet of plywood.

Note: Cutting 4x8 sheets of 3/4" plywood on a portable tablesaw is very challenging especially when the lumber yard's table saw is broken!

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    Not a great answer, but I'd go to a bookstore and measure what they have. Also, consider the books you will use it for. In a kids room, I'd make them extra deep. – JPhi1618 Dec 4 '15 at 17:03
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    How much deeper than "most books" have previous shelves been? Take that number and subtract it from your previous attempts' depth. That's your new number. The depth that "works best" is... the depth that works best, for you. FWIW all the Ikea bookcases are 11" total (so slightly less inside with the backing). – Jason C Dec 6 '15 at 0:32
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    This is too broad the way it is written. You could measure all the the books you have and take an average for your depth. Nothing wrong with books sticking out a little bit. – Matt Dec 6 '15 at 1:51
  • This is a rather old question that bubbled up from the depths, so this is too late for OP, but might help others: Head over to the Sagulator to determine if your shelves are thick enough to support the weight you expect to put on them and help calculate the distance between supports. – FreeMan Oct 5 '16 at 14:48

12" deep shelves are to deep for most books, again most books. I would make the bookshelf a "breakfront", the 2 lower shelves 12" deep above a 4" base or toespace, and step the front back at the 30-32" height and make the remaining shelves, 8, maybe 10" deep.

  • Thanks @Jack - I am going to make the top shelves 9.5" to optimize my plywood usage. – John M Dec 8 '15 at 17:37

"Most books" is far too broad. Books of what type? Standard paperpacks or oversized ones? Modern hardback novels or vintage/antique books?

Even assuming you mean regular paperbacks I don't think an average is the way to look at this. There may be a common, perhaps even typical, shelf depth for a bookcase but I've yet to see it myself, so an average of the various depths that are manufactured might result in a shelf as unsatisfactory (for some books certainly, perhaps even for all books) as your previous builds.

Surely the way to approach this is to measure your books and decide the clearance from the front that you like and bingo, you have your perfect depth? All that's needed after that is to build the bookcase accordingly.


Depends on your books. The ones I built last time used 1x12's; that's overkill but it does handle some oversized art books and lets me put two rows of paperbacks on a shelf (one upright, another tilted back in front of them).

Book sizes might vary by country, but a table of traditional sizes can be found at


And note that you want the shelf to be able to handle your larger books, not you average book.

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    According to This Old House, common default depth for single-depth built-in bookcase units is 11" to 12". I've seen barraster's bookcase units up to 16" deep; 20" for file-cabinet modules; subtract about an inch and a half to get interior dimensions; I've also seem them go shallower as part of a system which allows shallow units to be stacked above deep units to create a breakfront effect (though the commercially produced systems don't usually permit that kind of mix-and-match). – keshlam Dec 12 '15 at 1:23

Woodbin.com has some good design resources for furniture, check out http://www.woodbin.com/ref/furniture-design/shelves/ they suggest 10-12" deep as a common standard, they also have some good information on how wide vs how thick your shelf stock is, etc.


Standard bookshelves are 11 inches deep.


I have book shelves from two European manufactures. One is 12 inches deep and the other in 12.25 inches deep. I think book shelves are built that deep to make it more difficult for them to tip over as the books are usually towards the back and the shelves are against a wall. The suggestion of a break front is a way to have it both ways.

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    to compensate for the 'wobbly' nature of a skinnier bookcase I just used some large brackets to anchor the bookcase into a stud. – John M Dec 15 '15 at 16:07

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