Generally, there’s no ideal chapter length.
Depending on the length of your novel, you’ll likely have a rough chapter amount in mind. Whether this is 15, 20 or 40 will simply depend on your personal preference.
With my novels, especially my fantasy novels, the lowest word count in a single chapter is around 2000 while on the other extreme, my highest number breaches 10.000. As you can see, this fluctuates greatly. However I’d suggest not to go below 1500 per chapter; some readers tend to find this annoying as the chapter switches happen too quickly and don’t allow them to truly get into the story.
The most important thing, regardless of the length, is your transition from one chapter to another. Make it smooth. Don’t abruptly cut your chapter just because you want said chapter to have a set word count. It might even be best not to have a word count in mind at all. Write until that chapter is done and check the word count then. Your readers won’t make a problem out of this as long as you don’t either.
Keep in mind that many authors- like all other perfectionist artists in different creative branches- have the tendency to freak over the little details in an effort to be perfect and avoid what they perceive as possible future criticism. Criticism is a given. You can’t please everyone, but I truly doubt that even those who disliked your novel will be criticizing you on chapter lengths… unless, of course, it’s a 500 page novel and you only have 5 chapters (Way too few) or have 100 chapters (Way too many).
With me, my shortest chapters are usually full of action which, in my opinion, demands curtness and direct language. There’s more telling than showing here because here the telling is the showing. If you go into lengthy descriptions in action scenes, it slows your pace, thereby taking away the action and eliminating the sense of fictional adrenaline you want to instill in your readers’ minds. On rare occasions, I may also have a short chapter when there’s a major twist in the story which turns the whole thing upside down to add a sense of mystery and anxious expectation in the reader, but even these generally run around 3.000 words. My lengthiest chapters, on the other hand, depend on what’s happening in the story. Usually it’s a combination of multiple things, including short fast paced scenes, but there’s no clear cut example I can give without going into the specifics of the stories themselves. Typically lengthy chapters apply when a lot has to be revealed, but be careful not to overload the reader with information. Even in long chapters, make sure to balance the information carefully.
The main advice I can give is to go on feeling. End and begin a chapter where you deem fit as long as it keeps your novel’s dignity (and your own) intact.
P.S. I’ve spoken in “word counts” here above and I realize that some prefer an explanation in “page amounts”. You can simply calculate the pages by dividing the word counts above by 250 which is the typical amount of words per page in a book.