Average retail royalties fall in the 10% - 15% range on Hardcover sales, and 5% - 7.5% on Trade Paperback sales, generally.

Self-published authors can earn up to 70% royalties from their books, while most traditionally published authors make 5-18% royalties which they only receive after 'earning out'. That means the books sales have paid back  their advances and the publishers then start giving them a cut of book sales.