Some people say Upper MG and Lower YA are not categories because they wander between the YA and the children sections on the library shelves.
Some say it is fine to mention them and even pitch agents using the terms ‘lower’ and ‘upper’.
Everybody agrees that sometimes it is hard to decide if a book is MG or YA because the dividing line can be fuzzy.
YA is for 12 years and older, but the genre is divided between lower YA (12-14) and upper YA (15+).
MG is for 9-12 year old, but the genre is divided between lower MG (9-12) and upper MD (12-13).
While this is true, in fiction writing, Upper MG heroes can be as old as 15, but the voice is distinctly MG and the subject matter is less dark. YA heroes can be 16, but the voice is adult or childish. The teen voice is different from the adult voice and the pre-teen voice.
The point is publishers and agents need to have a clear idea where to place your novel.
Upper MG and lower YA are actually books for tweenagers, this age range between 10 and 15. The kids that age are usually too old for toys, but too young for boys/girls. They typically follow any fashion trend, defy authority, want independence but still need boundaries, try to find themselves, agree on everything even conflicting as long as they can make sense of it. They see everything black and white and are literal in their thinking – someone is all good or all bad. They read Harry Potter and the Diary of the Wimpy Kid, Watcher in the Woods, a Wrinkle in Time, or Anne of Green Gables.
MG tend to be clean.
MG novels are read by elementary/middle school students, so age 12 and younger.
Novels are shorter in length, as low as 15,000 words for novella and chapter books. Middle Grade is 35,000 words max for contemporary, mystery, humor, 45,000 max for fantasy/sci-fi, adventure and historical.
MG novels present one single plot, use simple vocabulary and a simple sentence structure. There is no swearing and the content of the story is innocent. There is only one point of view and one linear time period.
The action is focused outwardly. Outward events trigger a change inside.
The themes involve very little violence, no real romance, can be a little bit goofy.
Action comes mainly from imagination, so MG novels work well with fantasy and magic realism.
Pre-teens are still supervised by adults and have to respect their rules while exploring, so MG novels are mostly concerned by circle of friends and intimate worlds.
Upper MG novels are more sober, scarier novels than traditional MG novels.
Upper Middle Grade would be around 30k-40k words.
Upper MG for age 10-12: The Flame in the Mist by Kit Grindstaff (Jemma fights for her life against supernatural enemies to defeat evil and find her true identity); Percy Jackson & the Kane Chronicles by Ashley O'Neill (Percy is half god, half human and must save the world against powerful enemies from the Greek mythology).
Lower YA are also called books for advanced readers. They have edgy themes, but treated in a cleaner, friendlier manner, without any real danger or disastrous consequences.
Lower MG for age 12-14: If I stay by Gale Forman (Mia is pulled between wanting to die and wanting to live); Will Grayson by John Green and David Leviathan (story about sexual orientations and how it impacts two friends); Now You See Her by Jacquelyn Mitchard (Hope stages her own kidnapping to become famous. This story talks about pressure, identity, and knowing one's self.)
YA fiction is typically read by high school students, but more and more adults read it too.
Novels are longer in length.
YA — 70,000 words max for contemporary, humor, mystery, historical, romance, etc. 90,000 words max for fantasy, sci-fi, paranormal, etc.
Lucienne Diver says: “Middle grade generally hovers around 50,000 words and thereabouts. YA is generally more like 55,000 to 80,000 words, although we can all think of notable exceptions. If you’re just starting out, though, you’re going to want to keep your novel trimmed to a reasonable word count, because publishers like to keep the cover price down so that readers will be more willing to take a chance on an unknown quantity. In other words, the more the publisher has to spend on paper and printing, the more they have to charge. Also, the bigger the book, the fewer the bookstores can shelve in the allotted space.”(Live Journal)
Teen readers appreciate changes in point of view and in time period, multiple plots, a wider vocabulary and more complex sentences.
YA themes tend to be edgy, but handled with sensitivity and care.
From Jennifer Jensen in Suite 101: Young Adult Novel Guidelines says:
“The underlying themes, regardless of genre or topic, allow teens to examine deeper issues in a safe way: what their role in life is, the difference one person can make, the importance of relationships, coping with tragedy of any sort, etc. The younger set of YA readers can cope with scary subjects when they are at a distance—the character’s friend is doing drugs, not the character himself.”
Action is more gritty and realistic. Readers can handle themes like sex and homosexuality, masturbation, pedophilia, abuse, abortion, pregnancy, rape, cutting, suicide and drug use.
The characters are pretty independent and get in trouble on their own. They experience the story by themselves and they are more concerned by what is going on in the world. They discover the complexity of the world. They are psychology focused, but inner thoughts as important as outer events. The protagonist (16-year old and up) is interested in growth and learning from the world.