FUTURE TENSE

I´m doing something tomorrow. (For plans and arrangements - I´ve arranged, I´ve planned to do it.)

I´m going to a concert tomorrow. (I´ve even got the tickets already!)
Alice is going to the dentist on Friday. (She has an appointment.)
We´re having a party next weekend. (Everything is prepared!)

I´m going to do something. (I have decided to do it, my intention is to do it.)

I´m going to buy some new books tomorrow.
Sarah is going to sell her car.
I´m not going to have breakfast this morning. I´m not hungry.

Look at the sky! It´s going to rain. (Something is going to happen: it´s clear now that it´s sure to happen.)

will/shall


- Sue travels a lot. Today she´s in Madrid. Tomorrow she will be in Rome. Next week she will be in Tokyo.
- You can phone me this evening. I will be at home.
- We will probably go out tonight. (You aren´t sure yet.)
- I won´t be here tomorrow.
- Don´t drink coffee before you go to bed. You won´t sleep.
- I think I will pass the exam.
- Do you think the exam will be difficult?

* will - when you offer or decide to to something
- My bag is very heavy! - I will carry it for you.
- Bye! I will phone you tomorrow!
- I think we shall win. (Do not use shall with you/they/he/she/it.)
- Tom will be late.

Shall I.../ Shall we...? (Do you think this is a good thing to do? Do you think this is a good idea?)
- It´s warm in this room. Shall I open the window?
- I´m going to a party tonight. What shall I wear?
- It´s a nice day. Shall we go for a walk?
- Where shall we go for our holidays this year?

Present Simple with a Future Meaning

We use the present simple when we talk about timetable, programmes, etc (e.g., for public transport, cinemas, etc.)

- The train leaves Plymouth at 11:30 and arrives in London at 12:45.
- What time does the film begin?
- It´s Wednesday tomorrow.

You can use the present simple for people if their plans are fixed like a timetable:

- I start my new job on Monday.
- What time do you finish work tomorrow?

(Summarized from ESSENTIAL GRAMMAR IN USE by Raymond Murphy)