Future Forms: Will, Going To, Present

Explanation

Use will for predictions, offers and decisions made now. Use going to for intentions already formed and for predictions based on present evidence. The present continuous marks fixed arrangements and the present simple marks timetables. After when and if, use a present tense rather than will.

Examples

• I will call you when I land.
• Look at those clouds; it is going to rain.
• We are having dinner with them on Friday.

Common mistakes

• I will tell you when I will know.

  I will tell you when I know.

  No will in the time clause.

• Look at the sky, it will rain.

  Look at the sky, it is going to rain.

  Evidence-based prediction takes going to.

• I am going to call you, I promise.

  I will call you, I promise.

  A promise made now takes will.