Turn your word count into an estimated page count, spine width and full cover size for paperback printing.
Page count drives your print cost, your spine width and how the book feels in a reader’s hands. It also affects pricing: a thicker book costs more to print and usually needs a higher list price.
Most novels use 5 × 8 or 5.5 × 8.5 inches. Non-fiction and business books often use 6 × 9. A smaller trim adds pages; a larger one reduces them. Look at comparable books in your genre and match their size.
Your cover designer needs the exact spine width to build a full wrap. Cream paper is slightly thicker than white, so the spine is wider. Always use the final page count from your typeset file before sending the cover to print.