I calculated the average length of chapters in The Quest for the Legends a while ago and came to the conclusion it was somewhere between eight and nine pages. However, since then I've posted the longest chapter of the fic so far and such, so I think it's lengthened some since.
Ah, what the heck. I'll calculate it again. Chapters one to 39 of the ILCOE are 399 pages in Word total; that makes an average of roughly 10,23 pages per chapter. Chapter 40, which I'm writing right now, is 14 pages so far and going to become a lot longer than that, so that will bring the average up more.
So to make a long story short, my chapters get longer as I go on. Of the first twenty chapters, many of them are four, five or six pages, and all but three are ten pages or less. The shortest I've done since the four-page chapter sixteen, however, is a few six-page chapters, with an ever-increasing number of 'long chapters' that are more than twelve pages in length. Just to take since chapter 30, chapter 31 is 13 pages, chapter 32 is 26, chapter 33 is 10, chapter 34 is 20, chapter 35 is 8, chapter 36 is 12, chapter 37 is 27 (longest chapter yet), chapter 38 is 12, and chapter 39 is 7. That's an average of fifteen pages per chapter, with chapter forty, as I said, about to be longer than that too. Granted, there's been a lot more epic battles in chapters 3x than in most other parts of the fic, past and future, but it's still a visible trend towards getting longer.
Part of it, I think, is just that I feel like more stuff belongs in one chapter now than I used to. Today I'd combine a lot of those older, shorter chapters, I think. Another large part of it is that my battles have grown a lot longer - my longest battle ever is thirteen pages of just battling and is in chapter 37, while in earlier chapters I'd do a full six-on-six battle like that within the space of maybe four or five pages at the most. I got some complaints about the brevity of my battles, although not on this forum.
Generally, though, I have three classes of chapters in that fic. There's the "short chapters", which are ten pages or less; there's the "long chapters", which are something between twelve and twenty pages; and then there's the "ultralong chapters", which are more than twenty-five pages. I've never written a chapter that was eleven pages or anything between twenty and twenty-five, funnily enough.
Now, Morphic is another story (figuratively and literally). There my six chapters so far have all been around six pages, with the shortest being five and the longest eight. I don't see that changing very much, mostly because that story has no battles in it (not that I've planned, anyway) and really, battles are the most page-consuming thing in The Quest for the Legends by far.
. My chapters are normally six to eleven pages long before they start to make 'I want to end here' sounds 
