What Format & Trim Size Should My Book Be? An inside guide to book design and formatting

With the rise of e-books and various ways to read books, long gone are the days of books just being printed things that sit on your bookshelf. These days, you might have virtual bookshelves on your phone, Kindle, tablet, and laptop. But if you’re self-publishing a book, it can be confusing trying to figure out which formats you need to publish in: Mobi, e-pub, PDF? Have no fear—we’ll explain the various options and what they mean for your book, plus other common questions about book design including trim size. 

Print PDF 

Print PDF is the format that your book needs to be in so it can be printed and bound as a physical book. This is the same regardless of whether you have a batch printed in advance by a printing company or use a print-on-demand service such as Amazon POD (where the book is printed when a customer orders it and Amazon arranges it to be sent out to them). To get your print PDF file, you need to know the page size you’d like the book to be in.  

Note that print PDFs can be black and white or colour. There are also far more variations in design available for a print PDF compared to an e-book. Print book designs can be very flexible and creative.

Print trim size

Most nonfiction printed books fit into pretty standard “trim” sizes, which basically means the physical size of the book. The most common nonfiction trim sizes are: textbook (7″ x 10″), trade (6″ x 9″), and digest (5.2″ x 8.5″). There are also cute pocket-books (4.25″ x 6.87″) for short or fun reads, and different sizes for things like recipe books (often 8″ x 10″), photo books (known as “coffee table books”, often 8.5″ x 11″), and more.

If you’re not sure which trim size you prefer, have a wander over to your bookshelf and compare the sizes of your nonfiction books. Pick the size you like best and measure it to determine whether it’s textbook, trade, digest, or even pocket-book size. The best trim size often depends on the length of your book. For example, if it’s a relatively short book, avoid a larger trim size because the spine might be too narrow for the book’s title and your name. For a longer book, a smaller trim size might result in the book being too thick and bulky. You might also want to check the costs for printers and print-on-demand options.

e-Book formats: Mobi 

This is an e-book format and it’s used specifically on Amazon Kindle. This format is protected by Digital Rights Management (DRM), which essentially “locks” the book, meaning it can only be used on an e-reader or laptop that is linked to your Amazon account. This prevents file-sharing and book piracy. However, Amazon have recently approved authors to upload e-pub books on to their system, so you no longer need a separate Mobi file, which saves both time and money.

Note that all Mobi formats are black and white on Kindle devices, though this may differ with the Kindle app available for Android and iOS.   

e-Book formats: e-pub 

e-pub is the most common format for e-books and is used on all major e-readers such as Kobo (as well as most third-party e-readers). The e-pub format is responsive, meaning it re-sizes according to the device it’s being used on. For example, a book on an e-reader would have more words per page than the same book viewed on a phone. The images can also resize according to the screen size the book is being viewed on. 

e-pubs are generally created in a “step flow”, which means that any images or tables have to be shown above or below the text. Due to certain limitations in the e-pub format, images and text can’t appear side by side like they would in a PDF, so it’s worth bearing this in mind if you’re using other elements aside from text.  

Which to choose? 

Inevitably, the question is which format or formats to go for? Most authors opt for a print PDF file so they can have physical copies of the book, plus one e-book format so the book can be downloaded. Of course, it’s entirely your choice. You might be happy having just an e-book with no print version, just a print version and no e-book, or just Amazon Kindle and nothing else. If you go for a print book, decide which trim size you’d prefer, whether you want colour printing, and what binding you’d like (such as perfect bound, spiral bound, etc.)

How much does it cost? 

Book design costs can vary and this largely depends on the designer’s skill, the level of complexity you’d like for the design, and the page count. Unlike editing and proofreading, where the costs are based on word count, design costs are based on page count. Often, the designer will give you a per-page amount, then you can estimate the cost of the design. 

When estimating, it’s worth noting that your page count in Word will be different to your page count in print or e-book as a Word page is generally “Letter” or A4 size, whereas a book is smaller, which means fewer words per page. In print, you can expect 200-300 words per page (compared to say 500-600 in Word). To get a rough idea of your print page count, you can divide your word count by 250. Times that by the price per page from your designer and you’ve got a general idea. 

Can you format the book yourself? 

Of course, you can learn to design the book yourself. First tip: if you DIY it, avoid converting the book directly from a Word document to a PDF, as your line spacing, page size, and margin sizes might be incorrect. There are various online programmes that help you format the book yourself using simple templates, such as Canva, Scrivener, and ReedsyEditor. Template book designs can look plain and generic, but they can also be fine for a simple book that is mostly text. 

Obviously, templates don’t offer the same level of customisation you’d get from a professional designer and won’t be bespoke. So, if you want complex elements or a stand-out, unique design, then hiring a designer can be well worth the money. Or if you don’t want to spend time learning about step flows and page bleeds. Ultimately, it comes down to what you want, whether book design is within your budget, and whether you feel confident DIYing it. 

How long does formatting take? 

Book formatting time can vary depending on the page count and the complexity of the design. It might take a few weeks to decide exactly what you want, with a back-and-forth dialogue with the designer to modify samples. Once your design is finalised, it takes between a few days and a week for the designer to format the book. A 200-page book will take 2 to 3 days. After this, you usually get one free round of amendments to make any minor changes to the design or have the designer correct any typos identified during the final proofread. The time frame for this varies depending on the number of changes required. 

Want your book designed by The Book Shelf? 

We have an expert book designer who has formatted over 400 books. In our bespoke design process, we ask you for your preferences and any book designs you like, then our designer creates some samples for you to choose from. Then we finalise your design and the designer gets cracking! If you’d like your book designed by an expert layout designer, get in touch today.