When a future event is planned or arranged, use the present continuous or be going to:
- I’m meeting her tonight.
- I’m going to meet her tonight.
When a future event is timetabled or arranged as part of a regular and repeating schedule, use the present simple:
- My plane leaves at 6.00.
- The exam is on Thursday at 9.00 sharp. So don’t be late!
When a future action can be predicted because of evidence in the present, use be going to:
- Look at the sky! It’s going to rain.
- They’re too close, they‘re going to crash.
When a future action is an intention, decided at the moment of speaking, use will:
- My computer’s died. How are we going to finish the project?
Don’t worry, I‘ll pop home and get my laptop.
- It’s time for tea: can one of you call your father in from the garden?
OK mum, I’ll do it.