The Ultimate Guide to Hardback and Paperback Book Sizes in 2025

Choosing the right size of book isn’t just about aesthetics. It affects everything from production costs to how your readers experience your work. Drawing on years of industry expertise, this comprehensive guide will help you navigate the many options available, ensuring your book looks great and works well in its market.

This guide is designed to give you all the information you need to decide on the perfect size for your paperback or hardback.

How are books measured?

Before you dive into choosing a size, it’s important to understand how books are measured:

• Cover Dimensions: The height and width of your book’s cover are the primary measurements.
• Spine Thickness: This indicates how thick your book is and is typically measured in millimetres for accuracy.
• Trim Size: This is the final size of your book after it’s been bound and trimmed. Every measurement we discuss here refers to this ultimate, finished size.

Paperback and hardback books are measured by the size of the cover. First, take the measurement of the height of the book in either mm or inches. You will then need to get the measurement of the width of the cover in either mm or inches. The spine size of the width of the book, how thick the book is. This measurement is almost always in mm for accuracy.

What is the trim size?

Trim size is a term that you will hear about quite often when you are printing your book. This refers to the size of the book when it is in its final form. It is the size that the book will be when it is trimmed. Trimming of the book happens after the binding process (when the book block has the cover attached). All the above sizes we have talked about are referring to the trim size of the book.

What size should my paperback book be?

A regular paperback book can be any size that you want it. Most book printers will be able to accommodate sizes ranging from small A6 (105x74mm / 4.13×2.91 inches) pocketbooks to larger A4 landscape (297x210mm / 11.69×8.26 inches) books. The dimensions you decide to go for will depend on a variety of factors; look and feel, price, the genre of book, fiction or non-fiction and shipping costs. These factors will be covered in-depth in this page.

What size are trade paperback books?

Trade paperback books are normally the same size as their hardback equivalent but without the hard cardboard cover. They will have a thicker cover than a mass-market paperback book. A nice benefit of the trade paperback is having the nice, larger size book but without the bulk and weight of the hardback books. Trade paperback sizes are usually 5.5×8.5 inches – 229x152mm (9×6 inches) – 279x216mm (11×8.5 inches). Picture books for children tend to be in the range of 254x203mm (10×8 inches).

What is the standard size of a paperback book?

If you are producing a standard fiction book then you can be safe to set your book in one of the more common book sizes. Either B-Format (198x129mm – 7.8×5.07 inches) or A5 (210x148mm – 8.26×5.82 inches). There is no set standard paperback size for all books as the size differs with genre and market.

What size should I design my hardback book?

If you are deciding on a size for your hardback and you have published a paperback version already then you should work from the paperback size. All hardback book sizes are based on their paperback equivalent. You can view the table below to see what sizes of the book fit both types. Most hardback book sizes tend to be in the ‘trade’ or ‘mass-market’ size. Popular sizes for hardback books – 229x152mm (9×6 inches) – 279x216mm (11×8.5 inches). Having a larger size than those two sizes would normally be reserved for picture books.

What is the standard fiction book size?

Fiction books come in all different shapes and sizes. It would be a shame if every fiction book on the market were at the same size. Mass market paperback books tend to be 171x108mm (6.75×4.25 inches). A popular reason for this size is to save on production and shipping costs. If you are not going to send out hundreds of thousands of your books then you could go for something a little bigger. B-format books are a popular size of books around the world. In the US B-format books tend to be classed as 198x129mm (7.79×5.07 inches) and in the UK and Europe 210x135mm (8.26×5.31 inches).

What is the standard non-fiction book size?

Non-fiction book sizes are vastly different, more so than fiction books, then you have the hardback sizes to choose from. If you want to decide on a size for your non-fiction book, it would be best to go to local bookshops and have a look at some books which are in a similar genre. See what size they are and see what size will match your book. Some popular sizes non-fiction are A5 (210x148mm 8.26×5.82 inches), Royal (234x156mm 9.21×6.14 inches), B5 (250x175mm 9.84×6.88 inches) and A4 (297x210mm / 11.69×8.26 inches).

What is the standard children’s book size?

Children’s book sizes tend to be based on age. If you’re targeting younger readers up to 2 years then smaller books in the region of 190x190mm (7.5×7.5 inches) will be better. If your book is for more advanced readers in the age between 2 to 5 then the size of 178x25mmm (7×10 inches) and then for older reads from 5 years a size of 254x203mm (10×8 inches). Having a larger book can be better, you can have a more detailed image and more text on a page.

What is the standard photo book sizes?

Photobook sizes tend to be in a large hardback format. The size of the books is normally quite a bit larger than your regular fiction books. Photo books look lovely in any size but you should try and aim for upwards of B5 (250x175mm 9.84×6.88 inches). Blurb tends to be one of the more popular printing companies for photo books and you can see their sizes by clicking here.

What is the standard portfolio book size?

Portfolio book sizes are similar to photo books but not quite as large as they are not necessarily all about photos. If you’re producing a modelling photo book then of course, the larger the book the better, around A4 landscape, should be an aim (297x210mm / 11.69×8.26 inches). However, a nice size for a portfolio book would be around the size of B5 (250x175mm 9.84×6.88 inches).

What is the standard pocketbook size?

Pocketbook sizes are as the name suggests something you can fit in your pocket. A good idea is to think A6 (105x74mm / 4.13×2.91 inches). Maybe even a little bit taller but still a similar width such as 229x137mm (9.01×5.39 inches). This size of book is a popular size in the UK for map books – like this.

What is the standard comic book sizes?

A standard comic book is 257x168mm (10.11×6.61 inches). This doesn’t mean your book has to fit this size though. Your comic book size can be even bigger than this – 381x254mm (15×10 inches) is on the larger size of comic books but with a graphic novel this can look amazing.

What are the most common book sizes?

As you have probably guessed by now, there is no common book size in the publishing and printing industry. Many books fall under many different categories. If you were to try and pick a few common book sizes it would have to be the following; B-format (198x129mm 7.79×5.07 inches) – A5 (210x148mm 8.26×5.82 inches) – Trade Paperback (229x152mm 9×6 inches) – Royal (234x156mm 9.21×6.14 inches) and A4 (297x210mm / 11.69×8.26 inches).

Regional Differences: UK vs US Book Sizes

It’s also worth noting that book sizes can vary by region:

• B-Format Books:
  • UK: Approximately 210×135 mm (8.26×5.31 inches)
  • US: Approximately 198×129 mm (7.8×5.07 inches)

These differences, though subtle, can impact your book’s market appeal and compatibility with regional distributors.

Popular Book Sizes in the Publishing Industry

Here are some of the most commonly used sizes across various categories:

• B-Format: 198×129 mm (US) or 210×135 mm (UK)
• A5: 210×148 mm
• Trade Paperback: 229×152 mm (approximately 9×6 inches)
• Royal: 234×156 mm (approximately 9.21×6.14 inches)
• A4: 297×210 mm

Print-on-Demand Options

If you’re considering print-on-demand, here’s a snapshot of the sizes offered by some of the major players:

Createspace / KDP

• 5″ x 8″ (12.7×20.32 cm)
• 5.06″ x 7.81″ (12.9×19.8 cm)
• 5.25″ x 8″ (13.335×20.32 cm)
• 5.5″ x 8.5″ (13.97×21.59 cm)
• 6″ x 9″ (15.24×22.86 cm)
• 6.14″ x 9.21″ (15.6×23.4 cm)
• 6.69″ x 9.61″ (17×24.4 cm)
• 7″ x 10″ (17.78×25.4 cm)
• 7.44″ x 9.69″ (18.9×24.6 cm)
• 7.5″ x 9.25″ (19.1×23.5 cm)
• 8″ x 10″ (20.32×25.4 cm)
• 8.5″ x 11″ (21.59×27.94 cm)

Blurb

Blurb offers sizes tailored to short-run photo books, with options like:

• Trade Sizes:
  • 13×20 cm (Hardcover and Softcover variations)
  • 15×23 cm
  • 20×25 cm (with some restrictions on certain formats)
• Square Books:
  • Mini Square (13×13 cm)
  • Small Square (18×18 cm)
• Portrait & Landscape Options:
  • Standard Portrait and Standard Landscape formats with a range of sizes
• Large Formats:
  • Large Landscape (33×28 cm) and Large Square (30×30 cm)

Shutterfly

Ideal for photo books, with sizes including:

• 7×9 inches (178×229 mm)
• 8×8 inches (203×203 mm)
• 8×11 inches (203×279 mm)
• 11×8 inches (279×203 mm)
• 10×10 inches (254×254 mm)
• 12×12 inches (304×304 mm)
• 11×14 inches (279×355 mm)

How to Choose the Best Book Size for Your Project

Selecting the right book size is all about balancing form and function. Ask yourself:

• What Type of Book Are You Producing?
  Fiction, non-fiction, children’s, photo, or comic—each has its ideal dimensions.
• What’s Your Genre?
  The genre influences the traditional sizes your readers expect.
• Will Your Book Include Photographs or Detailed Graphics?
  Larger sizes can accommodate higher-resolution images and more intricate layouts.
• How Do Production and Shipping Costs Factor In?
  Smaller books may save on costs, while larger books might enhance the reading experience.
• Where Will Your Book Be Sold?
  Check out local bookstores or competitor titles to see which sizes dominate your market.

Ultimately, the best book size is the one that complements your content and meets your production and distribution needs.

In Conclusion

Choosing the perfect size for your paperback or hardback isn’t a one-size-fits-all decision—it’s a strategic choice that can enhance both the look of your book and its market performance. With this guide, you’re equipped with the knowledge and expertise needed to make an informed decision that aligns with your vision and business goals.

Remember, it’s your book, and every detail counts!

The following links will help you decide what book size to go for.

Standard book sizes
Look at the size of that thing
What size is a children’s book
Complete guide to book size covers