The Average Length of a Book: By Age, Range, and Genre

Before writing and publishing a book, make sure you know the average length of a book in your chosen genre.

When a reader picks up a book, they expect the approximate length of that book. Word counts impact a book’s target audience, which publishers show interest in it, and how much you can charge for it.

So what is the average length of a book? This is a wide range, but the average novel aimed at adult readers is around 90,000 words, with a range between 80,000 and 110,000. For non-fiction works, the average is slightly less at between 50,000 and 80,000 words. That said, some indie authors publish shorter, more specific non-fiction books around 30,000 words.

Truthfully, though, the answer depends on the genre of the book you’re writing or reading. You can count book length based on either average word count or an average number of pages, and this guide will help you determine what length is appropriate for a book you’re writing.

Average Length of a Book Depends on Genre

If you are considering writing a book or short story, you need to know the average word count before you start. This knowledge helps guide your story arc, ensuring you get the beginning, middle, and end in the right places. 

To determine the formatting and length of a book, you must look at the genre first. Children’s books have much different lengths than novellas and full-length novels. 

To keep things consistent, this guide will cover average word count rather than page count. Many factors affect the number of pages in the book, especially its formatting and the presence of illustrations, so word count is a better metric. Also, you can count words as you compose your document, and the number of pages of the finished work may change based on the publisher’s formatting.

Learn more about the types of genres for books.

Average Length for Adult Fiction Books

If you are writing fiction, here is the average length to expect based on the type of fiction book you write.

1. Adult Novels

Novel lengths typically fall between 50,000 and 110,000 words. The industry supports longer works, especially from established and trusted authors, but this is a good average range. Keep in mind that even among novels, genre impacts length.

2. Flash Fiction Stories

Flash fiction works are short stories that convey universal truths or emotions. The average length for these works is between 300 and 1500 words. 

3. Short Story

The average length of a book
Aim for between 1,500 and 30,000 words for a story

A great short story is slightly longer than a flash fiction piece. Aim for between 1,500 and 30,000 words for a story or book to fall in this genre.

4. Novellas

Novellas are shorter books often published as sequels or prequels for popular books. They often give the backstory of a character in the main story arc. The average length is between 30,000 and 50,000 words.

5. Romance Novels

Romance novels
Romance novels are between 40,000 and 100,000 words on average

Romance novels include both mainstream romance and sub-genre romance. These are between 40,000 and 100,000 words on average, with the sub-genre novels being slightly shorter.

6. Science Fiction and Fantasy Novels

The fantasy and science fiction novel niche tends to be a bit longer than other types of novels, so the author can create a fantasy or sci-fi world. Aim for 90,000 to 120,000 words for this genre.

7. Historical Fiction

If you are writing historical fiction, you’ll find the average range falls within the average word count for novels. The best historical fiction books fall between 80,000 and 100,000 words.

8. Horror, Mystery, Crime and Thriller Novels 

Though there are exceptions, the horror and mystery genres tend to be shorter adult fiction books. Traditional publishing aims for 70,000 to 90,000 words for this genre. Because they move quickly and include a lot of action, these do not have as long a word count. The best crime thriller authors adopt a similar approach.

9. Young Adult Books

YA novel writers often target adult readers. The sweet spot for the word length for these books is 50,000 to 80,000 words. Interestingly, many YA authors end up with a larger number of words in their sequels after they gain a bit of a following among their target readers.

Average Length for Children’s Fiction Books

Children have limited vocabularies and can’t read as long of books as their adult counterparts. Here are some publishing industry standards for children’s fiction works, based on age level.

10. Picture Books

Even though they often get read aloud, picture books have an industry-standard length. They tend to be between 300 and 800 words, with plenty of illustrations to help tell the story.

11. Early Reader Books

Early or easy reader books are for young, new readers. They feature minimal vocabulary that is in line with reading level, and they vary from 200 words to 3,500 words, increasing in word count as the reading level increases.

12. Early Chapter Books

After easy reading, most children move to chapter books. These still have limited vocabulary to line up with their reading levels. The average length, again depending on reading level, is between 4,000 to 10,000 words.

13. Middle-Grade Fiction Books

The middle grades, grades six through eight, need longer books but a limited vocabulary. The best word count for this age group is between 25,000 and 40,000 words. 

Average Length for Non-Fiction Books 

Non-fiction books can follow similar guidelines as age-group specific books. However, for books reaching adults, there are specific word counts that the publishing industry considers standard. The kind of book affects the word count in non-fiction as well.

14. Standard Non-Fiction Work 

If a non-fiction work is not a self-help or a biography or memoir, it has a pretty narrow range of between 70,000 and 80,000 words. This type of book includes political works, business books, science books, and similar non-fiction topics.

15. Memoir Books

Example of Memoir Book
The average length for this type of fiction is 80,000 to 200,000 words

memoir is someone’s autobiographical account of something that happened in their own life. It may not be an entire biographical account, but it does cover something the writer experienced. The average length for this type of fiction is 80,000 to 200,000 words.

16. Biographies

A biography is a book with a long potential range depending on the details in the subject’s life. The average range for this is 80,000 to 200,000 words. 

17. Self-Help Books

A self-help book gives guidance on how to do something. It may be personal growth or physical action, like how to do a craft. The average length for this is 40,000 to 50,000 words.

Does Word Count Matter?

Word counts for books is a fluid thing, but it does matter. Readers expect how long a book will be, and most publishers are looking for books they publish to hit the sweet spot for their readers.

That said, exceptions exist. For example, the first book in the Harry Potter series was perfect for young adult readers at 76,944 words. As the series progresses, the books get increasingly longer, and book five, Harry Potter and the Order of the Phoenix topped the list at 257,045 words. 

Since the series was a New York Times Bestseller, the word count didn’t matter. The books flew off the shelf. However, most writers need to stick within word count recommendations, especially when seeking to publish a book for the first time.

A Final Word on The Average Length Of A Book

The average length of a book depends on the subject, age-range, and type of book you choose. Literary fiction is usually longer than non-fiction, but even in those general terms, word counts vary.

Word count matters in the publication world because publishers need to publish books that appeal to their target audiences. Thus, they look for books that hit a certain range based on the genre.

If you are hoping to become a published author, sticking to word count ranges will help. 

Want more? Check out our guide how to write a book.

FAQs About The Average Length Of A Book

How long should a nonfiction book be?

A classic non-fiction book is usually between 70,000 and 80,000 words. Other types of non-fiction, like biographies, can be even longer, with upper limits of around 200,000 words.

How long should a fiction book be?

The average length of a fiction book depends on the age of its audience and the type of book. Picture books, for instance, can be as short as 300 words, whereas a science fiction novel can have upper limits of around 120,000 words.