Future: Will vs Going to
Level A2 · Tenses
Use will for a decision made right at the moment of speaking, a prediction based on opinion or general belief with no evidence, a promise, or an offer: I'll help you with that (spontaneous offer); I think it'll rain this weekend (opinion). Use going to for a plan or intention already decided before speaking, or a prediction based on visible evidence right now: I'm going to visit my parents next week (already planned); look at those clouds — it's going to rain (evidence you can see).
Form: will + base verb — will is a modal, so it never changes for any subject and never uses do: she will come, not she wills come; won't for the negative. Going to: am/is/are + going to + base verb, so the be-verb still agrees with the subject: I'm going to leave; he's going to call. Negatives add not to be (I'm not going to leave). Questions invert be and the subject (is he going to call?).
Will vs going to, side by side:
- Spontaneous decision (will): the phone's ringing — I'll get it! (decided right now)
- Prior plan (going to): I'm going to start a new job next month (already arranged)
- Opinion-based prediction (will): I think the team will win (belief, no proof)
- Evidence-based prediction (going to): look at the sky — it's going to rain (proof right now)
The most common mistake is using will for a plan that's already decided, or going to for a spontaneous, in-the-moment decision. If you decided before speaking, use going to: I'm going to see a film tonight (already planned), not I'll see a film tonight. If you decide as you speak, use will: this bag is heavy — I'll carry it for you, not I'm going to carry it for you.
Typical trigger words: right now, at the moment (will, for spontaneous decisions); already, next week/month, planning to (going to, for prior plans); I think, probably, I'm sure (will, for opinion-based predictions); look at, those clouds, about to (going to, for evidence-based predictions).