Trim size

What it means

Printers trim the paper to size after binding, which is where the name comes from. You choose the trim size before you lay out the interior, because it decides how much text fits on each page.

KDP says the most common trim size for books in the US is 6 by 9 inches. Its list also includes smaller sizes such as 5 by 8 inches, and larger ones. KDP counts a book as a large trim when it is more than 6.12 inches wide or more than 9 inches tall, and large trims cost more to print.

Different kinds of books lean toward different sizes. A novel is often a smaller, easy-to-hold size. A business or how-to book is often 6 by 9. Workbooks and cookbooks often go larger, to leave room for writing or photos. Picture books are often square or landscape. In the UK and Europe, sizes such as A5 are common.

Each printer has its own list of sizes, and not every size is offered with every paper or binding.

Why it matters when you sell direct

The trim size changes your page count, your print cost and your shipping cost. A bigger page means fewer pages but heavier paper; a smaller page means more pages. Pick a size your printer offers for every format you sell, so your paperback looks the same everywhere.

If you print with more than one printer, make sure both offer your size, or you will need two interior files.

How Lanternbee handles it

Lanternbee does not set trim sizes. You set up the printed book with BookVault or Lulu, in a size they offer, and Lanternbee sends them the orders from your store to print and ship.