Deciding on the Size of Your Book (Trim Size Guide)
The first and most important step in designing your book is deciding on its size. The dimensions—your trim size—must be set before layout, formatting or any other design work. Trim size affects visual appeal, practicality, production costs and readability.
Genre conventions help narrow the choice. Below is a quick guide (imperial and metric shown):
Recommended book sizes by genre
- Novels & fiction: Compact for easy handling. Common: 5″×8″ (127×203 mm) or 5.5″×8.5″ (140×216 mm). Economical to print, good for shorter page counts so the book doesn’t feel too thin.
- Nonfiction & memoirs: Slightly larger for readability and more content per page. Common: 6″×9″ (152×229 mm) or 7″×10″ (178×254 mm).
- Children’s books: Larger, often square, to suit illustrations. Popular: 8″×8″ (203×203 mm), 8.5″×11″ (216×279 mm), or 210×210 mm.
- Photography & art: Bigger pages or landscape for images. Examples: 11″×8.5″ (279×216 mm), 12″×12″ (305×305 mm), or A4 landscape 297×210 mm. Note: landscape formats can cost more to produce due to press sheet limits and cover/finishing considerations.
- Academic & reference: Functional and spacious for charts/tables. Typical: 8.5″×11″ (216×279 mm) or A4 210×297 mm.
Metric overview of common book sizes
| Category | Metric sizes |
|---|---|
| Novels | 127×203 mm, 140×216 mm |
| Nonfiction | 152×229 mm, 178×254 mm |
| Children’s | 203×203 mm, 210×210 mm, 216×279 mm |
| Art/Photography | 210×297 mm (A4), 300×300 mm |
| Textbooks/Reference | 210×297 mm (A4), 216×279 mm |
Setting up page size and margins in Microsoft Word
Once you’ve chosen a size, set the page dimensions in Word to match. The steps below reflect your directions, including mirror margins of 20 mm and a gutter of 0 mm:
- Open your document in Microsoft Word.
- Go to Layout on the ribbon.
- Click Size in the Page Setup group.
- Select a predefined size or choose More Paper Sizes to enter custom dimensions (e.g., 152×229 mm for 6″×9″).
- Click Margins in the Page Setup group.
- Select Custom Margins… at the bottom.
- In the dialog, set Top, Bottom, Left, Right to 20 mm.
- Change Multiple pages to Mirror margins so inner/outer margins adjust for binding.
- Set the Gutter value to 0 mm.
- Click OK to apply.
Note: Mirror margins ensure the inner margins are wider on printed spreads to accommodate binding and improve readability. For smaller page counts, the gutter can remain at zero because spine curvature is minimal.
