For me, a chapter is typically however long it takes to tell that part of the story, but personally, I prefer shorter chapters. I try to break it anywhere between 1000 and 2000 words. If it's over 2000 words it's too long, at least for the story I'm writing right now, because I want them to be a consistent length. But don't sacrifice the meaning for the form. If a chapter wraps up nicely way sooner and you really can't add any detail to it, then that's okay. If a chapter needs to be longer to finish up its part of the story, that's okay too!