In publishing terminology, trim size describes the height and width of the pages of a book. The trim size of a book has many ramifications for book design and layout. Larger page size can fit more words; the more words per page, the fewer pages overall.
How to Choose a Book Size?
Books come in different sizes, and the size of a book primarily depends on the genre. A book’s size plays a crucial role in its pricing. If you are writing a Fiction, the ideal sizes for your book are 5x8 inches, 5.5x8.5 & 6x9 inches. These are universally accepted sizes for a fiction book.
If you want to publish nonfiction content, say a book on history with Images and tables and maps or a product manual, the size 6x9 or 7x10 inches is best suited.
You can view all the trim sizes that we accept and which Genre is best suited with which size in this Table here