Future & Intention — ~(으)ㄹ 거예요, ~(으)려고, ~겠다

Attach ~을 거예요 to a consonant-final verb stem and ~ㄹ 거예요 to a vowel-final stem. It expresses a future plan, decision, or prediction. With first person it means 'I will / I'm going to'; with third person or weather it often means 'probably will'. The 거 comes from 것 (thing) + 이에요.

~(으)려고 marks the subject's intention or purpose. Followed by 하다 (~(으)려고 해요) it means 'I intend to / I'm planning to'. Followed by another clause it means 'in order to' and the two clauses must share the same subject. Use ~으려고 after a consonant, ~려고 after a vowel.

~겠 has three everyday uses: (1) strong personal will or promise — '저는 꼭 가겠습니다' (I will definitely go); (2) conjecture about a present/future situation — '맛있겠다' (it must be delicious); (3) softened polite intention in set phrases — '알겠습니다' (I understand / will do so). Attach ~겠어요 (casual-polite) or ~겠습니다 (formal).

Use ~(으)ㄹ 거예요 for a settled plan or neutral prediction (다음 주에 이사할 거예요). Use ~(으)려고 하다 to stress the intention or attempt, often something not yet fixed (이사하려고 해요 — I'm thinking of moving). Use ~겠다 for an on-the-spot decision, a promise, or a conjecture from evidence (제가 하겠습니다 / 힘들겠다). They overlap but differ in nuance.