“-ㄹ게요” or “-겠다”? When and Why to Use Each
-ㄹ/을게요
This ending is used to express a promise, voluntary decision, or a plan based on the speaker's own will, usually made in the moment and directed toward the listener. It’s common in conversations where the speaker reacts and commits to doing something.
Examples:
내일부터 공부할게요.→ I’ll start studying from tomorrow.(The speaker is making a promise or decision in the moment, often to someone else.)
Q. 누가 청소할래?A. 제가 할게요!→ I’ll do it!(The speaker is volunteering in response to someone’s question.)
Q. 계산하시겠어요?A. 네, 카드로 할게요.→ Yes, I’ll pay by card.(The speaker decides on the spot to pay by card. It’s a spontaneous decision.)
Note: While it often feels like a promise, the key point is that the speaker is showing willingness or making a decision at the moment of speaking.
-겠다
This ending can indicate a personal decision, future prediction, or inference. It’s often used when someone is thinking to themselves (internal monologue), or making a guess based on information or observation.
Examples:
내일부터 공부해야겠어요.→ I guess I should start studying from tomorrow.(A self-directed decision or realization. It’s not a promise to someone else.)
기차가 곧 도착하겠어요.→ The train will arrive soon.(An assumption or prediction based on current information.)
내일 비가 오겠어요.→ It will probably rain tomorrow.(A weather prediction.)
김치찌개가 맵겠어요.→ The kimchi stew must be spicy.(Guessing based on experience or appearance.)
지수씨는 진짜 피곤했겠어요.→ Jisoo must have been really tired.(A strong inference based on observation or situation.)
Note: ‘-겠다’ can show anything from a mild guess to a strong conclusion depending on the situation and tone.