DocumentationDesigning the book
Page and margins
Trim size, the four margins, and bleed. Why the inside margin grows with the page count, and when you need bleed at all.
Trim size
The finished size of the book, after the printer cuts it.
| Group | Sizes |
|---|---|
| Paperback | 5 × 8″, 5.06 × 7.81″, 5.25 × 8″, 5.5 × 8.5″, 6 × 9″, 6.14 × 9.21″, 6.69 × 9.61″, 7 × 10″, 7.44 × 9.69″, 8 × 10″ |
| Square | 8.25 × 8.25″, 8.5 × 8.5″ |
| Letter | 8.5 × 11″ |
| Metric | A5 (148 × 210 mm), A4 (210 × 297 mm) |
All sizes shows the full list; Custom takes any dimensions.
Changing trim size repaginates the book and changes its page count, which changes the spine width and the minimum inside margin. Settle it before making a cover.
The four margins
| Margin | What it is |
|---|---|
| Inside | The binding edge, also called the gutter |
| Outside | The fore-edge, under the reader’s thumb |
| Top | Above the running head, not above the text |
| Bottom | Conventionally deeper than the top |
The diagram in the panel is drawn to scale from your four values, so a fore-edge twice the gutter looks like one.
Because a wider gutter narrows the text measure, applying that fix repaginates the book and can push it into the next band. Run the check again afterwards.
Bleed
Range 0.25 to 2 mm, in steps of 0.05.
Bleed is extra image area past the trim line, so that artwork meant to run to the edge of the page still does after the printer’s cut wanders by a fraction of a millimetre.
You need bleed only if something touches the edge of the page — a full-bleed photograph, a chapter band running to the trim. A book of prose needs none, and setting it changes nothing except the sheet size the printer receives.
Recto and verso
Inside and outside margins mirror: on a right-hand page the inside margin is on the left, on a left-hand page it is on the right. This happens automatically — you set inside and outside, never left and right.
Check it in PreviewTwo-page spread, where facing pages are shown as they will be bound.