BEG 8 | ~(으)ㄹ 거예요 vs ~(으)ㄹ게요

They are both used for future actions, but in different contexts.

*In service industries, employees use this to tell the customers to do something. “이 쪽으로 오실게요. (“You will come this way.” with the honorific suffix ~시~) as if the listener is volunteering to do so. By doing so, they are trying to sound polite and not assertive.

CONJUGATION

C+을게(요).

먹다 to eat              먹을게(요). “I will eat.”
                                You are at a dinner table with your friend, but s/he is on the phone.
You’re too hungry to wait, so you tell your friend “I’ll eat first.”

                                나 먼저 먹을게.

“나 먼저 먹을 거야.” sounds like a declaration of your future plan that is irrelevant to
your friend like “I am going to eat, and it’s none of your business”. For that reason, this
can sound very strong and possibly angry. Due to the offering meaning of ~(으)ㄹ게, it
sounds softer as if you are asking for their understanding!

있다 to be (location)   있을게(요). “I will be [somewhere].”
Your roommate is asking if you want to go to the gym together, but you are too
tired. You are telling him/her “I will just stay in the room.”

                                    나는 그냥 방에 있을게. 오늘 너무 피곤해.

“나는 그냥 방에 있을 거야.” sounds like a declaration of your action without
considering the listener even if the listener is involved in the situation. For that reason,
this sounds too strong and possibly angry or rude.

V + ㄹ게(요).

가다 to go               갈게(요). “I will go.”
You are at a party with your friend and about to leave. You inform your friend that you
will be leaving: “I’ll get going.”

                                나 갈게!

“나 갈 거야.” sounds like a declaration of your future action that is irrelevant to your
friend like “I am going to go, and it’s none of your business”. By saying “나 갈게.”, you
are leaving a possibility for the friend to say no or to leave together because it shows
that you are aware your action will affect them, and they are involved in your plan.

하다 to do               할게(요). “I will do.”
You are offering to help by saying “I will do it (let me do it).”

                                내가 할게. (to friends) / 제가 할게요. (polite)

Because the other person is inherently involved when you offer to do something for
them, you use ~(으)ㄹ게(요).

You are telling your friend that you will text them later.

                                나중에 문자할게!

Because the other person is inherently involved when promising something, you use ~
(으)ㄹ게. If you say “문자할 거야.”, it sounds like a declaration of your future action
regardless of the listener’s feelings. For that reason, this sounds strong.

ㄹ Irregular: DON’T CHANGE ANYTHING (ㄹ drops and you treat it like vowel)

살다 to live                             살게(요).          “I will live.”
벌다 to make money                        벌게(요).          “I will make money.”

ㅂ Irregular: ㅂ BECOMES 우 + ㄹ게(요)

돕다 to help    1) 도우 + ㄹ 게(요).
2) 도울 게(요).

저도 도울게요. I’ll also help. [volunteering, offering, promising]

 굽다 to grill, to pan fry        1) 구우 + ㄹ 게(요).
2) 구울 게(요).

    고기 내가 구울게. Meat, I will grill. [volunteering, offering]
(Remember Korean word order is flexible? 고기 is the object, but it can come
at the beginning or the sentence when you want to emphasize and get the
listener’s attention to it.)

ㄷ Irregular: ㄷ BECOMES ㄹ + 을게(요) (Almost only these two are irregular)

듣다 to listen              들을게(요).       “I will listen.”
걷다 to walk               걸을게(요).       “I will walk.”