Deciding on the right book size may seem like a bit of a no-brainer; however, it can shape everything from your book’s readability to its printing cost and overall appeal. Standard book sizes (also known as trim sizes) are the most commonly used dimensions publishers use when producing paperbacks, hardcovers, and even eBook editions.
If you’ve found yourself here, you’re probably looking to work out which size is right for your book – and the answer isn’t always so straightforward. Different genres, formats, and publishing platforms all come with their own expectations.
Today at What We Writing, we’re sharing with you our clear book size chart, a breakdown of standard sizes by genre, and practical tips to help you decide on the best option for your project – whether you’re self-publishing or prepping a manuscript for print.
What Are Standard Book Sizes?
Standard book sizes are the term used to describe dimensions for printed books. In publishing, these are usually referred to as trim sizes – the final width and height of a book after it has been printed and cut. As an example, a typical novel may have a trim size of 5.5 x 8.5 inches (roughly 14 x 21.6 cm), whereas larger non-fiction releases typically come in 6 x 9 inches (approximately 15.2 x 22.9 cm).
These dimensions are usually listed in both inches and centimetres, depending on whether you’re working with US or UK-based printers, so it’s handy getting to grips with both.
Choosing the right book size matters more than you may first think. It can influence:
- Printing costs – larger books naturally use more paper and therefore are more expensive to produce
- Readability – the size influences font, spacing, and how comfortable the book is to hold
- Genre expectations – readers tend to associate certain sizes with specific types of books (for example, compact sizes for fiction and larger formats for workbooks or guides)
To summarise, trim size isn’t just a technical detail – it plays a fundamental role in how your book ends up looking, feeling, and performing.
Standard Book Sizes Chart (Quick Reference)
Here’s a quick overview of the most common standard book sizes used in the publishing world. These trim sizes cover the majority of fiction, non-fiction, and larger-format books, and are widely used by printers and self-publishing platforms.
| Format | Size (inches) | Size (cm) | Common Use |
| Small paperback | 5” x 8” | 12.7 x 20.3 cm | Compact fiction, novellas |
| Standard paperback | 5.5” x 8.5” | 14 x 21.6 cm | Most novels and general fiction |
| Trade paperback | 6” x 9” | 15.2 x 22.9 cm | Non-fiction, memoirs, self-help |
| Large format | 8.5” x 11” | 21.6 x 27.9 cm | Workbooks, manuals, textbooks |
| A4 (UK standard) | 8.27” x 11.7” | 21 x 29.7 cm | UK printing, reports, workbooks |
These sizes are all considered to be “standard” because they’re cost-effective to print, widely accepted by retailers, and familiar to readers. If you’re not sure where to begin, most self-published books fall comfortably within the 5.5” x 8.5” x 9” range.
Standard Book Sizes By Genre
Choosing a book size isn’t all about your personal preferences – it’s closely tethered to genre expectations. Readers are used to certain formats, and sticking to them helps your release feel both professional and market-ready.
Fiction
Most fiction books are printed in smaller, comfortable sizes such as 5” x 8” or 5.5” x 8.5”, with 6” x 9” also common for longer novels.
These sizes work well because they’re:
- Easy to hold and read for long periods
- Cost-effective to print (important for novels with higher word counts)
- Familiar to readers, particularly in genres such as romance, thriller, and literary fiction
If your novel is on the longer side (80,000+ words), a larger trim size such as 6” x 9” can help reduce the page count and printing costs.
Non-Fiction
Non-fiction books are usually printed in 6” x 9” or larger formats such as 7” x 10” or 8.5” x 11”.
These sorts of sizes suit non-fiction because they:
- Allow for clearer layouts, including headings, diagrams, and images
- Provide more space for margins and notes
- Create a more structured, authoritative feel
For guides, manuals, or textbooks, larger sizes improve usability and make the content far easier to navigate.
Memoir & Self-Help
Memoirs and self-help books often use 5.5” x 8.6” or 6” x 9”, straddling between fiction and non-fiction in style.
This balance works well because:
- Memoirs benefit from a novel-like reading experience
- Self-help books often need slightly more space for headings, exercises, or quotes
- Both genres target readability and accessibility, rather than dense formatting
If your book includes prompts or exercises, aiming for a 6” x 9” size provides you with a bit more flexibility.
Children’s Books
Children’s books can differ dramatically, but the most common sizes we’ve found in our local bookstores are 8” x 8”, 8.5” x 8.5”, and 8.5” x 11”.
Larger formats are preferred because they:
- Showcase illustrations more effectively
- Create a more appealing visual experience
- Are easier for younger hands to handle and follow along with
Picture books especially benefit from square or oversized layouts that lend some room for the artwork to stand out.
Coffee Table & Art Books
These books are typically printed in larger formats such as 8.5” x 11”, 9” x 12”, or sometimes even bigger.
The reasoning here is simple:
- They prioritise visual impact over portability
- Larger pages allow for high-quality image reproduction
- The size contributes to a more premium, display-worthy feel
Unlike standard paperbacks, these books are designed to be browsed, displayed, and revisited rather than read from cover to back.
By aligning your book size with your genre, you aren’t just following convention – you’re improving your audience experience, production efficiency, and market expectations all at once.
Paperback vs Hardcover Book Sizes
Paperback and hardcover books usually share similar trim sizes; however, there are some notable differences in how these dimensions are used.
Paperbacks are usually more flexible when it comes to size, with common formats such as 5.5” x 8.5” and 6” x 9”. They’re designed to be portable and cost-effective, making them the go-to standard option for most fiction and self-published novels.
On the flip side, hardcovers are usually slightly longer and more structured in their feel. Even when the trim size is the same, the added binding, thicker covers, and margins can all make the book appear bigger and more premium.
This ties nicely into pricing and reader expectations. Paperbacks are usually the cheaper version and regarded as everyday reads, whereas hardcovers are priced higher and usually associated with collectability, durability, and first-release editions.
Standard eBook And Cover Sizes
eBooks don’t have any fixed “page sizes” like print books, but cover dimensions still matter – especially for how your book looks online. Most platforms recommend a portrait-oriented cover with a standard size of around 1600×2560 pixels, which follows a 1:1.6 aspect ratio.
This ratio guarantees that your cover looks balanced across devices, from e-readers to mobile apps.
Platforms like Amazon Kindle Direct Publishing come with their own guidelines; however, they generally align with this format.
A high-resolution image (at least 300 DPI) is also paramount for ensuring your cover is sharp and professional-looking.
The key difference when it comes to eBooks is that your cover is often seen as a small thumbnail, rather than full-size. That means clarity is crucial.
Practical tips:
- Keep text large and readable – avoid any thin fonts or overcrowded designs
- Test your cover at thumbnail size – if it’s hard to read when it’s small, it won’t stand out in any search results
A well-sized, clear cover can make all the difference in grabbing attention and driving clicks.
How To Choose The Right Book Size (Step-By-Step)
Choosing the right book size doesn’t need to be guesswork. If you break it down into a few key factors, you can soon narrow in on the best option for your project.
1. Start with Genre Expectations
Your genre lends you a strong starting point. Most novels sit comfortably at 5.5” x 8.5”, whilst non-fiction and self-help often opt for a 6” x 9” or larger. Readers are used to these formats, so sticking closer to them helps your book feel professional and familiar from the off.
2. Consider Your Word Count
Longer books benefit from slightly larger trim sizes. If your manuscript sits at over 80,000 words, a 6” x 9” format can help reduce the page count, which in turn lowers printing costs. Shorter books, like novellas, often work better in smaller sizes to avoid appearing too thin.
3. Factor in Printing Costs
Book size directly affects how much you’ll pay to print. Larger formats use more paper; however, smaller formats can increase page count. There’s a balance to be struck here – 6” x 9” is often the most cost-efficient middle ground for most self-publishing authors.
4. Check Your Distribution Platform
Different platforms support different trim sizes. As an example, Amazon Kindle Direct Publishing and IngramSpark both offer a wide range of options, but not every size is available everywhere. Choosing a widely supported size (like 5.5” x 8.5” or 6” x 9”) ensures a smoother distribution.
5. Think About Reader Experience
Finally, consider how your book will feel in a reader’s hands. Smaller books are more portable and immersive, larger ones are easier to scan through and better for visual content. The right size needs to match how your audience is likely to engage with your novel.
By working through these steps, you can confidently choose a trim size that balances practicality, cost, and reader expectations.
Common Mistakes To Avoid
Choosing a book size may appear straightforward; however, a few common mistakes can make your book appear less professional or cost more to produce than necessary.
- Ignoring genre expectations
Picking an unusual size for your genre can instantly make your book feel “off” to readers. For example, a thriller in a larger academic-style format may not feel intuitive or market-ready. - Choosing size before content is finalised
Your trim size needs to come after your manuscript is finished. Word count directly affects page count, which can change both cost and readability. - Over-prioritising aesthetics over practicality
A unique or oversized format may look appealing; however, it can increase printing costs and limit where your book can be sold or distributed. - Not checking platform requirements
Self-publishing services like Amazon Kindle Direct Publishing and IngramSpark have specific size constraints. Choosing outside these can create unnecessary formatting issues. - Forgetting readability and handling
Larger books might look impressive; however, they can be uncomfortable to hold. Smaller books are far more portable, but run the risk of feeling cramped if poorly formatted.
Avoiding these mistakes helps guarantee your book doesn’t just look professional but also performs well in production and with readers.
Check Out Our Guide To The Costs Of Self-Publishing
Wrap Up
Choosing the standard book size comes down to juggling genre expectations, word count, printing costs, and how you want your audience to experience your book. Whilst there are many trim sizes available, most books fall comfortably within a few standard formats such as 5.5” x 8.5” or 6” x 9”.
The key is to not overthink things – there’s usually a clear “best fit” once you consider your content and audience. With the chart, genre breakdowns, and step-by-step guide above, we’ve hopefully provided a far clearer picture of which direction to take.
If you’re planning your own book, use this as a reference whilst you refine your manuscript and prepare for publishing.
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James has been passionate about storytelling ever since he could hold a pen. Inspired by the epic fantasy and historical dramas he devoured in his youth, his work now centers on dark, psychological tales featuring intense, introspective characters and atmospheric, gothic undertones. In 2025, he founded What We Writing to share his creative journey and the lessons he’s learned along the way with fellow writers and passionate storytellers.
