According to the WaniKani statistics page, you can learn all N5 kanji when you finish level 16, all N4 kanji after finishing level 27 and all N3 and N2 kanji after finishing level 51. When you reach level 60 which is the last level, you will learn around 80% of N1 kanji. When I started to prepare for JLPT N2, I was at level 35 and most of the kanji was really in N2 levels so it actually helped me a lot during the exam preparation.