A Comprehensive Guide to Book Sizes (and a Brief History)

You saunter through your local bookstore, browse the shelves for that hard-to-find book you’ve been looking for, and your aesthetic sensibilities are offended by the dramatically different book sizes, known as trim sizes, ahead of you. Believe it or not, there is a system for those sizes and for some historical reasons.

Standard size? Sandman has no time for your standard size!

What drives different book formats? The simplest answer is money. Hardcover and other large books cost more to print and have a higher price. Many (but not all) debut and literary authors see their books going straight to paperback because the publisher doesn’t want to take that risk. As Edward Wyatt from The New York Times said, “Even critically acclaimed literary novels often have a short shelf life in hardcover, with half to three-quarters of books shipped to stores often returned to the publisher unsold.”

When you see a book in hardcover, you know that the publisher is confident that the book will sell well. Only after a good hardcover run will these books be released in paperback and reach a new audience.

A Brief History of Book Formats

This history of the printed page goes back almost as long as we’ve had the written word. For the sake of brevity, let’s look back to 1455 and the Gutenberg Bible. This masterpiece was printed as a folio, that is, a single large piece of paper folded once. Each page measures 12″ by 17.5″, with four pages printed on each large piece of paper. However, there were no standard sizes during this period, and since each small publisher followed its own rules, not all folios were the same size. Do not believe me? Check out the rather exhaustive list that Harrington Rare Books has compiled.

These folios were quite large books, often illuminated, and only the very wealthy could own them. How do you sell more books? Make them smaller and cheaper. Take that folio size and fold it in half, printing eight pages on each paper. Now you have a quarto where each page measures approximately 9″ by 12″. Fold that again and you have an octavo. Measuring 6″ by 9″, the octavo is a size that has become commonplace on our bookshelves today.

But it’s far from the only size out there.

Fiction Book Format

Being the largest market for books, fiction also has the widest range of formats. These are the standard sizes.

chart of fiction book sizes, created by Chris M. Arnone

hardcover books are usually 6″ x 9″. Sounds familiar? Yes, it’s that regular octavo format, still in use.

Trading Paperbacks have a few different sizes ranging from 5″ by 8″ to 6″ x 9″. You might call these the “fun paperbacks” when you see them.

Mass market paperbacks are also known as pocket paperbacks and measure only 4.25″ by 6.87″. You can find these not only in bookstores, but also in supermarkets and grocery stores.

Book formats for non-fiction and memoirs

When you go from fiction to non-fiction, you see a lot of overlap in sizes. The magnitude of the mass-market paperback, however, is solely the domain of fiction. On the other hand, some non-fiction books are even larger in size than fiction.

chart of non-fiction book sizes, created by Chris M. Arnone

Paperback memoirs can be as small as 5.25″ by 8″. Other nonfiction and memoir can be 5.5″ x 8.5″ and 6″ by 9″.

hardcover fiction shares the 6″ by 9″ octavo size with fiction, but there is also a 7″ x 10″ size, although not very common.

Dimensions of children’s books

Children’s books are something completely different, aimed at younger eyes and clumsy fingers. So these books are usually big and not all of them are taller than wide. The three standard sizes are 7.5″ by 7.5″, 7″ by 10″, and 10″ by 8″. Again, these are just the standard sizes, although you can certainly find books that fall outside of that.

chart of children's book sizes, created by Chris M. Arnone

Other book formats

Some books, like school books, are often large. Standard sizes here are the old octavo 6″ by 9″, 7″ by 10″, and 8.5″ by 11″. graphic novels usually come in 6.625″ by 10.25″, the same as comic books, although hardcovers add some extra size without increasing the actual page size. Then of course there are photo bookswho basically pick any size you want and hold coffee tables all over the world because you want to see every detail in the images.


Actually, any type of book can be just about any size. They may be miniature because a publisher wants a challenge or because Abraham Lincoln wanted Union soldiers to carry the Emancipation Proclamation in their pockets. Especially for art and nature books, they can grow so big that they even need their own furniture. From huge collector’s editions to tiny pocket guides, what’s printed on the page matters most.

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