Updated: Mar 3
"Middle grade" is usually defined as kids between 8 and 12 year old. As any parent or teacher will attest, that is a huge range. And within that age range, some kids develop reading skills earlier than others. As you may expect, the range of books that count as middle grade cover a huge range of literature.
The content that an eight year old loves might not hit home for a tween. Conversely, parents won't buy their eight-year-old kid a book that covers more mature content.
This is why I appreciate it when authors and agents say "Upper Middle" or "Lower Middle" to distinguish between the younger and older readers.
One way to measure the difference between upper and lower middle grade is book length. Jon S. Lewis wrote that there are different word counts for upper versus lower level books:
Upper Middle Grade: 60,000-90,000 words
General Middle Grade: 45,000-60,000 words
Lower Middle Grade: 20,000-45,000 words
The reason it is important to distinguish between upper and lower middle grade is that if you say you have a "middle grade" manuscript that is 80,000 words, you can raise a red flag in some agents' minds. They're expecting something less than 60,000 words. I'm not going to point fingers, but I've seen blogs and videos that say not to exceed even 55,000 words per book.
Looking at the top 10 middle grade sellers (according to Google) published each year, the average word count was usually over 60,000 words. In 2010 and 2020 the averages were in the mid 80,000s. Nearly as many middle-grade books land above 100,000 words as land in the 35-60,000 word range, which is wider than Jon S. Lewis pointed to as a "General Middle Grade" range.
I know that many agents represent the whole spectrum of middle grade, which is AWESOME! But knowing an agent's or publisher's range within middle grade would help authors target who to send manuscripts to, and when to save everyone's time.
There are free online tools for calculating the readability of texts. A book that hovers around fifth or sixth grade readability, like Rick Riordan's Percy Jackson series, is only appropriate for readers at or above that reading level.
Advanced young readers often read more difficult books, so readability is only one measure.
For authors, it seems important to distinguish between lower middle and upper middle grade, because the books are different. A 20,000 word, 3rd grade reading level book is vastly different from an 85,000 word, sixth grade reading level book.
I'd love to hear your thoughts on whether you agree or disagree.