A book length calculator that shows how long bestsellers in your genre are, from real books, and how your book compares.
Pick your genre to see how long its bestsellers are, then compare your book and set your finish date.
Your genre
Your book
How long #1 bestsellers are
A bestseller's pages are the middle of its editions (hardcover, paperback, large print), from Open Library. Each sets a different number of words on a page, so compare pages at your own layout.
Recent #1 bestsellers in this genre
- Game On by Navessa Allen (2026): 384 pages
- Atmosphere by Taylor Jenkins Reid (2025): 352 pages
- Caught Up by Navessa Allen (2025): 370 pages
- Mate by Ali Hazelwood (2025): 368 pages
- Say You'll Remember Me by Abby Jimenez (2025): 352 pages
When you'll finish
Type your words above and your pace here to see your finish date.
What you type or upload stays in this browser. Page counts come from each font's own letter widths, and from line breaks measured on 24 public domain books.
This free book length calculator shows how long bestsellers in your genre are, and how your book compares.
It's built on real books: every New York Times #1 since 2010, and the Times' business and advice bestsellers. Page counts come from Open Library.
Here's how long books run in each genre, why pages don't turn neatly into words, and how to set your finish date.
What is a book length calculator?
A book length calculator tells you how long a book in your genre usually is, and how long yours will be.
Most use 1 table of word counts with no source. This one uses 854 bestsellers, and shows its sources.
How long are bestsellers in each genre?
Here's the page count of the middle book in each genre, and the range the middle half falls in:
| Genre | Middle book | Middle half | Bestsellers |
|---|---|---|---|
| Fantasy | 512 pages | 388 to 780 | 54 |
| Historical fiction | 479 pages | 380 to 824 | 17 |
| Mystery and crime | 418 pages | 358 to 478 | 52 |
| Thriller | 416 pages | 385 to 465 | 223 |
| Literary and general fiction | 414 pages | 377 to 465 | 13 |
| Romance | 384 pages | 352 to 485 | 41 |
| History | 360 pages | 323 to 450 | 14 |
| Memoir and biography | 344 pages | 280 to 460 | 124 |
| Politics | 340 pages | 272 to 402 | 36 |
| Business and money | 304 pages | 251 to 352 | 125 |
| Self-help | 272 pages | 228 to 312 | 155 |
Fantasy runs longest: a quarter of its bestsellers pass 780 pages. Self-help runs shortest, and 3 in 4 of its bestsellers stay under 312 pages.
Why pages don't turn straight into words
Each page count is the middle of a book's editions: hardcover, paperback and large print. Each edition sets a different number of words on a page.
Your own layout changes it too. 80,000 words is 206 pages at 6" × 9" in EB Garamond at 11 pt, and 266 in Libre Baskerville.
So the calculator sets your book in pages at your layout, beside the bestsellers. The book page count calculator shows how each choice moves it.
How to set your finish date
A finish date comes from your pace, not a rule of thumb.
At 500 words a day, 5 days a week, 50,000 words takes 100 writing days: 140 days on the calendar. Type what you've written, and the calculator counts only what's left.
How to use the book length calculator
Your word count carries over to the other book tools.
Book Length Calculator FAQs
Questions about book length? Here's what to know.
A book length calculator shows how long books in a genre usually are and how long yours will be.
This one uses New York Times bestsellers since 2010, with page counts from Open Library.
A book should be about as long as the bestsellers in its genre.
The middle New York Times bestseller runs 272 pages in self-help, 304 in business, 416 in thrillers and 512 in fantasy.
A self-help bestseller is 272 pages in the middle, and the middle half runs 228 to 312 pages, across 155 New York Times advice bestsellers since 2010.
A business bestseller is 304 pages in the middle, and the middle half runs 251 to 352 pages, across 125 New York Times business bestsellers since 2010.
A fantasy #1 bestseller is 512 pages in the middle, the longest middle book of any genre in the data, and a quarter of them pass 780 pages.
The time to write a book is the words left divided by your daily pace.
At 500 words a day, 5 days a week, 50,000 words takes 140 days, and the book length calculator works out your own date.
Yes, the book length calculator is free, with no sign-up.
The math runs on your device.
The book length calculator is for authors planning a book, who want to know how long it should be for its genre and when they'll finish it.
The words to pages calculator converts your word count, and the book page count calculator adds spine width and printing cost.
See all my free tools.
Navid Moazzez
AI business strategist & AI OS builder
Navid Moazzez helps creators and founders master AI and build their own AI Operating System (AI OS) to automate their business and life.
Navid.me is reader-supported. When you buy through links on this site, I may earn an affiliate commission. Learn more.
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