I haven’t really counted, well, until now.
If I look at Harry Potter (using google, rounding), I’m getting HP SS/PS 4500, HP CS 4700, HP PoA 4900, HP GF 5200, HP OotP 6800, HP HBP 5600, HP 5500 words/chapter. More googling, Hunger Games is about 3700 words/chapter. The Hobbit, 5000 words/chapter. Fahrenheit 451 is 15400 per chapter (only 3 chapters).
Overall, my personal guideline, I find it useful to me, letting me know when it might be time to cut back, or divide a chapter, especially if I’m getting long winded/overly-verbose in a particular section that I’m not trying to make the focus to the chapter. In the end, I know when I read my material, they generally don’t seem too long/short, so it works for me.