A printing model where books are only printed when someone orders one, so you never need to pay for or store thousands of copies upfront.
Print on demand is a publishing model where individual copies of a book are printed only after a customer orders one. Instead of doing a traditional print run of 2,000 or 10,000 copies and storing them in a warehouse, your book exists as a digital file at a printing facility, and each copy is produced and shipped as orders come in. Services like IngramSpark and Amazon's KDP Print handle the printing, shipping, and returns. You upload your files, set your price, and they do the rest.
Print on demand demolished one of the biggest barriers to publishing: the upfront cost of printing. Before POD, self-publishing meant gambling thousands of dollars on a print run and hoping you could sell enough copies to break even, often while your garage filled up with unsold books. Now you can have a professionally printed paperback available worldwide with zero inventory risk. The trade-off is a higher per-unit cost, which means slimmer margins, but for most indie authors the math still works out in their favor.
Modern POD printing is excellent. The paper stock, binding, and cover printing are virtually indistinguishable from traditionally printed books. The technology has come a long way from the early days.
POD costs more per book than a bulk print run. Price your book so that your royalty per sale actually makes sense after the printing cost is deducted. Run the numbers before you set your retail price.
KDP Print gives you Amazon. IngramSpark gives you everywhere else. Many indie authors use both to maximize their reach while keeping Amazon's fast shipping for the biggest marketplace.
Go to Amazon KDP's royalty calculator or IngramSpark's compensation calculator and plug in your book's specifications: page count, trim size, and your desired retail price. Calculate your per-copy royalty. Then compare what you'd earn selling 500 copies via POD versus ordering a bulk print run of 500 at an offset printer's quoted price. This exercise shows you exactly when POD makes financial sense and when it doesn't.