Will and be going to

Will + infinitive

Will has a neutral meaning. We use it to talk about facts in the future:

  • I’ll be 31 next month.
  • Next year will be 2018.
  • She’ll finish her study next year.
  • The sun will rise tomorrow.

We use will for instant decisions or agreement at the moment of speaking:

  • – There’s no milk. – Really? In that case, I’ll go to get some.
  • There’s a postbox over there. I’ll post these letters.

We use will for prediction based on opinion:

  • I think the Conservatives will win the next election.

We use will for a prediction about the future:

  • One day people will travel to Mars.

We use will in offer/invitation/promise:

  • I’ll help you tomorrow. if you want. /offer/
  • Will you come to lunch? ~Yes, thank you. /invitation/
  • I’ll pay you back next week. /promise/

Will does not express an intention /we use going to/:

  • It’s her birthday. She’s going to have a meal with her friends. NOT She’ll have a meal.

But we often use be going to for an intention and will for the details and comments:

  • We are going to have a meal. There’ll be about five of us. Oh, that will be great.



Be going to + infinitive

We use be going to for an intention, something already decided to do before the moment of speaking:

  • I’m going to sell my car.
  • He’s going to quit his job next month.
  • I’m going out. I’m going to post these letters.

We use be going to for a prediction based on something we can see /or hear/ now:

  • There isn’t a cloud in the sky. It’s going to be a lovely day.
  • This bag isn’t very strong. It’s going to break.