Hello 할 거야 and 할게 is quite similar. You use both when you want to talk about future for example: 학교에 갈거야 and 학교에 갈게 both mean 'I will go to school' However, it is a bit different on how you use it Main difference is that when you say 할거야, it implies that that's your intention and you won't change your mind if someone says something. However when you say 할게, you are either saying it because of what someone else said or you want to see what they say. You could say it is more polite than saying 할거야 Let's look at the difference 공부할 거야 - here you're just simply saying that 'i will study' 공부할게 - this could be in a situation where your mom tells you that you should study and you can reply '알았어. 공부할게' In this situation, you cannot say '알았어. 꽁부할거야' because it would not sound natural as you are going to study because your mom told you to, it was not your original intention 겠어요 is commonly used when you want to say something like 'i think' or 'i assume' Some examples are '아프겠어' - that must hurt or '좋겠어' that must be good It is usually used as a reaction to what other person says. So if someone says to you that they are going on a holiday somewhere really nice you can say '우와 진짜? 좋셌어' and it means 'wow really? That must be good/awesome. Hope this doesn't make you more confused ^^