Set a novel interior between 10 and 12 points, and judge the result by eye on paper rather than by the number. Most trade fiction sits around 10.5 to 11 points, depending heavily on the typeface.
That hedging is not vagueness. Point size is not comparable between typefaces, so the number alone does not tell you how big the text looks.
Why the Number Misleads
A typeface's point size describes its body, not its letters. What the reader perceives is the x-height, the height of a lowercase x, and that varies enormously between faces at the same nominal size.
Legge and Bigelow measured this across 51 seriffed fonts and found "the x-height fraction... ranged from 0.36 to 0.55, with a mean of 0.45". So the largest-looking face is more than half again as large as the smallest at an identical point size.
Their worked example: "the x-height fraction of Times New Roman is 0.45, slightly less than half the body size, so 12 point Times New Roman has an x-height of 5.4 points."
The UK Association for Accessible Formats makes the same point and supplies the replacement metric:
"A given numerical text size such as 12 or 14 point will vary from typeface to typeface. For example, Arial 14 point appears larger than Times New Roman 14 point. So, although point sizes are used for convenience, they are not precise. A more precise measure is x height, which is the height of the letter x in the given typeface. The recommended x height for 12 point is 2 mm, for 14 point it is 2.3 mm, for 16 point 2.8 mm, and for 18 point approximately 2.9 mm."
The practical consequence: changing typeface changes your effective size. Swapping a face with a 0.36 x-height fraction for one at 0.52 makes the text look substantially larger at the same point size, and changes the page count too.
What Real Books Actually Measure
This is the useful data, and it is rarer than it should be. Legge and Bigelow measured the type in 200 hardcover novels published since 2000, 100 paperback novels, and 360 US newspapers:
| Mean x-height | |
|---|---|
| Hardcover fiction | 0.24 degrees, 1.68 mm |
| Paperback fiction | 0.24 degrees, 1.66 mm |
| Newspaper text | 0.23 degrees, 1.64 mm |
Note how tight that is. Hardcovers, paperbacks and newspapers all cluster within a hundredth of a millimetre, which tells you the convention is real and consistently applied.
Those are x-heights, not body sizes. Working back through the mean seriffed x-height fraction of 0.45 puts typical trade fiction at roughly 10.5 points of body size, though that conversion is arithmetic on their figures rather than something the paper states.
The reassuring finding is how much latitude you have. Legge and Bigelow: "There is a 10-fold range of print size from approximately 0.2° to 2° for which people with normal vision can achieve maximum reading speed", and "Evidently, newspaper and book typographies are compatible with the critical print size for normal vision."
So book typography sits at the bottom edge of the range where normal readers hit full speed. It works, and there is no headroom below it.
The Accessible Minimums
Here the numbers are explicit, and they are larger than trade practice.
| Body | Standard print | Large print |
|---|---|---|
| UKAAF | 12 pt minimum, 14 pt recommended | 16 pt minimum, 18 pt recommended |
| RNIB | "usually 10 or 12 point" | 16 to 18 point |
| APH | 18 pt minimum |
UKAAF: "For clear print use 12 point text size minimum, though 14 point is recommended. For large print use 16 point minimum, though 18 point is recommended. 24 point is sometimes known as giant print."
The American Printing House for the Blind draws a line that surprises people: "A document is not actually 'large print' unless it is in a font size 18 points or larger." So a 14 point edition is enlarged print, not large print.
This is a genuine conflict with book design convention. Novels measure a mean x-height of 1.68 mm. UKAAF's 12 point clear-print minimum corresponds to an x-height of 2 mm. Typical trade fiction therefore sits below the minimum accessible size, and well below the recommended 14 point.
That is not a reason to set your novel at 14 point, which would produce a very different object. It is a reason to know that a large print edition is a separate edition, and that pushing your body size up slightly costs you little.
One counterintuitive warning from UKAAF, worth knowing before assuming bigger is always better:
"A few people with sight problems prefer smaller print than 14 point. For example, someone with tunnel vision who only sees a few letters at a time but who has good acuity may be slowed down by larger print."
What Deckle Uses
Deckle's default body size is 11 points, which sits in the middle of trade practice and slightly above the measured mean for novels.
Two consequences worth understanding:
Type size drives page count, which drives everything. A larger body size means more pages, which means a wider required gutter, a thicker spine and a higher printing cost. Deckle's estimated page count updates as you change it, so the tradeoff is visible before you export.
Changing typeface changes the apparent size. Because Deckle's 24 body fonts have different x-height fractions, moving from one to another at the same 11 points can noticeably change how large the text looks and how many pages it fills. Reset the size by eye after switching, not by the number.
If you want to move toward the accessible minimums, 12 points is a legitimate choice for a novel and costs perhaps 8 to 10 percent more pages. That is a real cost, and it is your call rather than a rule.
For the faces themselves, see choosing a typeface for a book interior and serif vs sans serif.
Common Mistakes
- Comparing point sizes across typefaces. The same number looks different in different faces.
- Copying a point size from another book. Without knowing its typeface the number means little.
- Setting the size on screen. Print it at final trim size and read it on paper.
- Assuming trade sizes are accessible. They sit below UKAAF's clear-print minimum.
- Calling a 14 point edition large print. APH's threshold is 18 points.
- Forgetting the page count consequence. Type size changes cost, spine and gutter together.
FAQ
Q: What point size should a novel be? A: Typically 10 to 12, depending on typeface. Measured novels average an x-height of about 1.68 mm.
Q: Why does my book look bigger than another at the same size? A: Different x-height fractions. They range from 0.36 to 0.55 across seriffed faces.
Q: Is 11 point too small? A: For most readers, no. It is below the accessible clear-print minimum of 12 point, which is a separate question.
Q: What size is large print? A: 16 point minimum per UKAAF, 18 recommended. APH says nothing under 18 counts.
Q: Does a bigger size always help low vision readers? A: No. UKAAF notes some readers with tunnel vision are slowed by larger print.