Use will to talk about something that you think will happen.

• I think he’ll win the election.
• He will be a good doctor.

Use be going to to talk about something that you see is going to happen (there is present evidence).

• Don’t drive like a crazy man. We’re going to have an accident!
• The doctor said I’m going to have a girl.

Sometimes there’s little difference between will  and be going to for predictions. Compare:

• The conference starts in 10 minutes. We are going to be late. (=I can see that we cannot be at the conference in 10 minutes)

We need to hurry up. We’ll be late for the conference. (=I think we will be late)

👀 We use will / won’t + infinitive for making instant decisions, offers, and promises.

👀 We don’t use the present tense.

👀 When an offer is a question, we use Shall I…? or Shall we…? Shall I pay? Shall we do the washing-up?

DECISIONS

I won’t stay for dinner. I think I’ll go home earlier.

OFFERS

I’ll help you with your homework. Shall I open the window?

PROMISES

I’ll always love you. I won’t tell anybody