Average Weight of A Paperback Book / Hardcover Book. I've taken some common books sizes and found their average weights. I did 2 common sizes for Hardcover books and since paperbacks are a little more varied I did 5 sample sizes. I've listed their averages by Dimensions/Pages/Weights. LxWxH in inches/Avg # of Pages/ Size and Average number of pages in a Hardcover/Softcover book. HARDCOVER 8x6x2/ 735pgs- 1lb 15oz avg 8.5x5.5x1.5/460pgs- 1lb 2oz avg PAPERBACKS 9.5x6x1--/370pgs- 15oz avg