Glossary

What is trim size?

Updated

Trim size is the finished width and height of a printed book after the pages have been cut. It is chosen before the interior is laid out, because changing it later re-flows every page and changes the page count.

The sizes people actually use

TrimUsually used for
6 × 9 inThe self-publishing default. Non-fiction, memoir, most trade paperbacks.
5.5 × 8.5 inA slightly more compact non-fiction and workbook size.
5.06 × 7.81 inMass-market-ish fiction; feels like a novel from a shop.
8.5 × 11 inWorkbooks, manuals, anything with worksheets to fill in.
Sizes vary a little between printers. Check the list your print-on-demand service publishes before you lay anything out.

What it decides for you

  • The page count, which sets the printing cost and therefore your royalty.
  • The spine width, which is calculated from the page count — so the cover artwork cannot be finished until the interior is.
  • The margins. The inner margin has to be wider than the outer one, because the binding swallows part of the page. That extra is called the gutter.

Related terms

All glossary terms

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