Usually it’s Times New Roman, 12 pt font, double spaced, but it can depend on the publishing house. If you plan on submitting professionally, then I recommend:Chuck Sambuchino’s Guide to Formatting and Submitting Your Manuscript It’s the best, covering different kinds of submissions, how to format your query letter, and how to get the specifics down. Everything from margin size, to typeface, to paper, to helpful submission hints.
Chapter length usually depends on who you’re writing for, a Middle Grade chapter is usually going to be shorter than an adult novel. Chapter breaks are basically just scene breaks, end them where they feel natural. Try to limit yourself to fifteen pages a chapter, about 4,000-7,000 words in an 80,000 word novel. The goal is to make sure you have a pace which keeps the story moving and end each chapter in a place where it wraps up something but also leaves a question which encourages your reader to keep turning the page.
Chapter breaks, really, are something to hammer out when you’re revising. When you’re writing the first draft, don’t worry about font, or size, or line breaks, or what size the margins should be, or anything else. If writing in Franklin Gothic 14 pt font is where you’re most comfortable, go for it.
Sometimes, I write in times new roman, 12pt, single spaced because it’s less intimidating than something that looks official. I can’t write in any program other than Word. I import the pieces of my novel into the Scrivener and use that for formatting scenes into chapters, but not for my first drafts.
When I’m revising and want to rethink where I’m breaking my chapters, I read each one and pay special attention to when I start to getting tired or bored. Now, I’m Type 1 ADHD, I have a really short attention span. But there are plenty of times in my writing where I just keep going, I’ve ended up with 10,000 and even 15,000 word chapters. However, when I edit, I try to read like a reader not a writer. I ask myself: if this was another author’s work, would I be getting bored? Skipping ahead? Tired? When my brain goes ‘ugh so long’ and I don’t want to keep going, that’s when I know it’s time to break the chapter.
Finishing a chapter feels like an accomplishment. Each chapter has it’s own beginning and it’s own end, even though it’s part of a larger story. Each one a reader completes should feel like they’re making progress in the story and keeps them eager to turn the page. I feel like I need to get the end of that chapter and I can put the book down, I hate stopping in the middle. I do this with RPG questlines too, my brain goes “need to finish this quest!” because each quest is it’s own little story inside the bigger one and if I don’t finish it I’ll lose track.
There is no real rule of thumb for how long a chapter should be. You have to go with what feels right. (And then find out if your beta readers agree with you.)
My biggest personal theory that I bring to the table with revising is this: I do not believe I owe my time and attention to anyone when it comes to my entertainment. If I get bored with a book, skip ahead in a movie, get tired with a game, then I put it down. I’m a huge completionist when it comes to stories that grab me. If I find a show I like, I’ll binge watch all the episodes. I read the Spellsong Cycle and Protector of the Small at least once every year. I own several different copies of each book in the Wheel of Time because I perpetually lose them and need a complete collection, okay? When I love a book or a series, I’ll hole up on a weekend and finish it that weekend. I speed read, I can read 600 page books within 6 hours. If I love it, I don’t put it down. Or if I do, I always pick it up again.
However, my Steam library is full of games I tried but didn’t click with me. There are seasons of some of my favorite shows I’ve never watched because I lost interest. My shelf is full of books I never got past the first twenty pages on or only managed to force myself to the halfway point. Many of those are books which sell well, are very popular, and have legions of fans but I didn’t find I cared. So, I stopped.
I don’t owe my time to anyone just because I bought, borrowed, or rented it. This includes my own writing.
When I revise, I take that attitude in with me. I read it like I would if I were reading it for the first time and the beauty is that I get to change it. When I revise, I create the book that holds my attention. The one I want to read.
I don’t know if any of that helps, but I hope so.