With the many different forms for making the future simple (will, going to, present simple and present continuous), specific uses of the tense may help demonstrate which form is best to use. One area that the different forms can have an impact on meaning is when describing planned and unplanned events.
Unplanned events in the future simple
The will future form is normally used for an action or event in the future that has not been previously arranged. This may be because it has been recently decided, or it is a response to new information.
- They will not move. (They have recently made this clear.)
- I’ll answer the phone. (In response to it ringing.)
Exactly what makes a future event planned, and how recently the event was decided, may be a question of context.
Planned events in the future simple
A future action or event that has been arranged, or caused, before speaking is normally demonstrated with the going to future form. Usually it is not used for recent decisions.
- He is going to visit his parents in Scotland. (It is already planned.)
- They are going to build a house across the road.
This can include events that we believe will be completed, even if they are not arranged or scheduled, because they are likely.
- The caretaker is going to clean this mess up eventually. (We expect he will, because it is his job.)
The distinction between a planned and unplanned future action or event can be unclear, or flexible, so be aware that will and going to can be used in similar ways.