The standard line spacing for a printed book is 1.3× to 1.45× the font size (called “leading” in typography). For an 11pt font, that means 14.3pt to 15.95pt leading. This is tighter than Word’s default (1.15×) and much tighter than double-spacing (2.0×). Getting line spacing right is the second-most impactful formatting decision after font choice — too tight and readers feel cramped, too loose and the book looks padded.

Line spacing by genre

GenreRecommended SpacingWhy
Literary fiction1.35–1.45×Moderate, comfortable reading pace
Romance1.3–1.4×Tighter = faster reading, matches pace
Thriller / suspense1.25–1.35×Tight spacing creates urgency
Fantasy / sci-fi1.35–1.45×Standard for long books
Horror1.3–1.4×Tight, claustrophobic feel
YA fiction1.4–1.5×More generous for younger readers
Middle grade1.45–1.55×Even more open
Poetry1.0–1.2× within poemsStanza spacing separate from line spacing
Nonfiction1.4–1.5×Room for structural hierarchy
Self-help1.4–1.5×Open, inviting feel
Large print1.4–1.5×Comfort and accessibility

Line spacing by trim size

TrimSpacingLines per Page
5” × 8”1.25–1.35×30–34
5.25” × 8”1.3–1.4×31–35
5.5” × 8.5”1.35–1.45×32–36
6” × 9”1.4–1.5×33–38

Smaller trims need tighter spacing to fit enough text per page. Larger trims can afford to be more generous.

Page count impact

Line spacing is the second-biggest driver of page count after font size. For an 80,000-word novel at 5.5×8.5 in 11pt Garamond:

SpacingLines/PageTotal PagesKDP Cost
1.2× (very tight)38~235$3.94
1.3× (tight)35~255$4.18
1.35× (standard)33~280$4.72
1.4× (comfortable)32~295$4.90
1.5× (generous)29~325$5.26
2.0× (double)21~460$6.88

Going from 1.35× to 1.5× adds ~45 pages and $0.54 per copy. Double-spacing (which is a manuscript format, not a book format) would add 180 pages and $2.16 per copy.

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Common spacing mistakes

1. Using Word’s default spacing

Word’s default line spacing is 1.15× with 8pt spacing after paragraphs — neither of which is appropriate for a book. Book interiors use:

  • 1.3–1.45× line spacing (not 1.15×)
  • First-line indent instead of space between paragraphs
  • No extra space after paragraphs (except at scene breaks)

2. Double-spacing for the interior

Double-spacing is for manuscripts (submitted to agents/editors). Books are never double-spaced. If your book interior is double-spaced, it looks like a submission, not a published book.

3. Using space-between-paragraphs instead of first-line indent

This is a web/screen convention. Printed books use:

  • ✅ First-line indent (0.25–0.35”) with no extra space between paragraphs
  • ❌ No indent with extra space between paragraphs (this is for web pages and technical documents)

Exception: some modern nonfiction uses block paragraphs (no indent, space between). But fiction should always use first-line indents.

4. Inconsistent spacing throughout

If Chapter 1 has 1.35× spacing and Chapter 5 has 1.5× spacing, readers will feel something is wrong even if they can’t articulate what. Spacing must be identical throughout.

What “line spacing” actually means

TermDefinition
LeadingThe distance from one baseline to the next (typographic term)
Line spacing / line heightSame as leading, expressed as a multiplier (1.35× = 135%)
Single spacing1.0× — baseline to baseline equals the font size. Too tight for books.
1.15× (Word default)Slightly open. Still too tight for most books.
1.3–1.45× (book standard)The sweet spot for printed books.
Double spacing (2.0×)Manuscript format only. Never for published books.