Ahem, so i will start off by saying while you don't need to maybe add your word count at the bottom of the page? (to be honest i just like seeing how many words i read in the end of the book) secondly, according to professional literature: 

꣑ৎ A short story: under 7,500

꣑ৎ Novelette: between 7,500 and 17,500

꣑ৎ Novella: between 17,500 and 40,000

꣑ৎ Novel: over 40,000

[NOT in the chapters, it's more all together word count for all the pages!!]