What type size should I use?

In Book Design Made Simple, we suggest type sizes that should work in most situations for adult readers. But there are so many other situations! What about children’s books? What about large type books? Reference books? In this article we’ll suggest solutions for these kinds of books. And we’ll only discuss printed books; with ebooks, the reader can enlarge or reduce the type size to whatever works for them.

Understanding typefaces and type sizes

First, let’s look at the parts of a typeface that are related to its size.

The x-height and other aspects of a font can make a big difference in how much type will fit on a line or a page. Here’s a small example to illustrate this:

The example above shows only one word. Imagine if you extended the copy to a paragraph or an entire page. So when making your choice, keep the type size plus the x-height in mind and note how condensed or expanded the individual characters are. You want your type to be readable (not squintable!), but blocks of type must also fit your overall space requirements.

In addition, you might want to read up on the color of type pages in this excellent article by Joel Friedlander (The Book Designer). In the case he discusses, the color refers to the density of type on a page.

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Comparing with competing books

We are always sending you out to compare your book with others! This time, though, maybe you can stay home and look through your own book collection.

Either in the library, the bookstore, or at home, find books that are comparable to yours: the same audience (academic, general public), the same genre (romance, reference, picture book, etc.), and the same general age group.

Gather up your comparison books and start measuring. The easiest way to measure type is with a point and pica gauge or a pica ruler. You can buy an acceptable one at Michaels or a slightly better kind on Amazon.

Here’s what to measure:

• The height of the capital letters, which are usually 2/3 of the type size.
• The leading (pronounced “ledding”), which is measured from the base of one line to the base of the next. The base is the red line under the word “Example” in the illustration above.
• The width of the block of type on a typical page.
• While you’re at it, you might as well make note of the number of lines on a full page. That will help you later on if you want to calculate how many characters appear on a full page.

Other ways to measure

You can also measure without a ruler by using InDesign, or even Word (with a lot more effort). Simply find 2 or 3 lines of type in your comparison book, and measure the line width. In InDesign, make a text frame of that width and type out those same lines of text, using the same font. (To identify a font, try this online tool from MyFonts.) Then try different type sizes until you find the one that makes the two samples match. In InDesign, you may play with tracking also, if you think the letterspacing in the comparison book looks a bit squished or stretched out.

Next, figure out the leading in your sample. Add some lines of nonsense type so you have a large enough sample: maybe 10 lines of type. Or fill a whole page that’s the same height as in your comparison book and then count the lines. To fill a text block with type quickly in InDesign, put your cursor where you want the text, then choose Type>Fill With Placeholder Text. The text frame will fill with lorem ipsum to the bottom in whatever paragraph style is selected. Alter the leading in the entire type sample until you match the original. You will probably have to print out your samples to make side-by-side comparisons.

Matching the typeface

It takes a lot of practice to identify a font successfully by eye, especially now that new ones come out every week. But these days you can get help online. Try this online tool from MyFonts.

Also, sometimes, if you’re really lucky, you’ll find a note (called a colophon) in the last pages of a book telling you exactly what typeface was used. Yessss!

Next we’ll give you a practical range of type sizes for various kinds of books.

Type sizes for adult trade books and textbooks

First, what is a trade book? It’s one that’s sold to the general public, including paperbacks, hardcovers, fiction, and nonfiction. Textbooks are not trade books simply because they’re sold to a specialty market. So in other words, trade books are normal, everyday books.

Generally speaking, the maximum width of a line of text should be 5 inches (30 picas) for a textbook or adult trade book. Exceptions can be made in coffee table books and art books.

Here’s the commonly used range for adult trade books:

• 11–12.5 point type on 14–16 point leading.

Here’s the commonly used range for college textbooks:

• 9.5–11 point type on 11–13 point leading.

Other textbooks—for elementary or middle school level, for instance—use the same sizes as trade books for those ages. See below.

Type sizes for children’s books

The range of type sizes for children’s books is huge. I used to wonder why the type for younger children—who probably have perfect eyesight—is so big. But now that I’m a grandma, I think it’s because the person reading the book aloud is usually an adult who might be pointing out every word as they go along. And who might also be holding it a great distance away in order to fit kids on their lap. Whatever the reason, the type sizes for kids of all ages seem to work quite well.

Here’s the commonly used range for picture books:

• 12–48 point type on 16–48 points leading

The enormous differences in sizes and spacing is quite striking. Older, classic picture books seem to have smaller type and sometimes more words for the adult to read. Some picture books teach early sight reading and use large type to help with this. Some are best read aloud for a pleasurable aural effect (rhymes and alliteration, for instance), so type size might depend more on how much type fits on a page.  Think about who is going to read the words in your book and what you want the children and the adults to experience.

Here’s the commonly used range for the early reader:

• 14–18 point type on 18–36 points leading

Here’s the commonly used range for middle grade books:

• 11–13 point type on 16–27 points leading

Here’s the commonly used range for middle school to high school:

• 11–12 point type on 14–16 points leading

Type sizes for large print editions

Not many self-publishers think to produce a large type edition of their book. In fact, there are several publishing companies that specialize in doing this, so if your book becomes popular, you might contact them to see if they’d create a large print edition for you. After all, they already have marketing schemes and teams in place, and they know their audience well.

If you want to do it yourself, here’s the commonly used range:

• 15–18 point type on 17–20 point leading.

16 point type on 18 point leading is the most common. Hint: The big publishers seem to use Times Roman most of the time; it’s a good space saver but also very readable.

Type sizes for reference books and directories

When you need to squeeze a huge amount of material into a manageable amount of space, you have to go small. Consider using two or more columns; it can save you space while also saving the reader’s eyes. Be sure to choose a really clear typeface. Hint: Try Helvetica.

Here’s the commonly used range:

• 8–9  point type on 9–11 points leading.

We hope this guide helps you decide on a type size for your book, but don’t stick to it religiously. There are many other kinds of books, and lots of hybrids, too. We’ve written about cookbooks, workbooks, and coffee table books in other articles on this site.

Best of luck with your publishing adventure. Type size is just a small piece of the whole.

Read more: InDesign book template » Includes all the basic styles described in the book.
Read even more: Combining serif and sans serif fonts » Learn the tricks to successful mixing.
And read more: Calculating book page count using word count » What could be more useful?
And even more: Typeface vs. font » Why you should know the difference.

Book Design Made Simple. You can do it yourself.