Future Simple has two different forms in English: will (устаревшая форма shall) and be going to.

Be going to is used to express:

1. A plan
It expresses the idea that a person intends to do something in the future. It does not matter whether the plan is realistic or not. (намерение что-то сделать в будущем)
•    He is going to spend his vacation in Hawaii.
•    She is not going to spend her vacation in Hawaii.
•    A: When are we going to meet each other tonight?
     B: We are going to meet at 6 PM.
•    I’m going to be an actor when I grow up.
•    Michelle is going to begin medical school next year.
•    They are going to drive all the way to Alaska.
•    Who are you going to invite to the party?
•    A: Who is going to make John’s birthday cake?
     B: Sue is going to make John’s birthday cake.
2. An intended action
She is going to visit her parents tomorrow.
3. Evidence that something will definitely happen in the near future
Ann is going to have a baby.      It’s going to rain.
4. Things we are sure about or we have already decided to do it
He’s going to be promoted. (Decision is ready).

Both will or be going to are used to express a prediction about the future:

(what might happen in the future). In the following examples, there is no difference in meaning.
•    The year 2222 will be a very interesting year.
•    The year 2222 is going to be a very interesting year.
•    John Smith will be the next President.
•    John Smith is going to be the next President.
•    The movie «Zenith» will win several Academy Awards.
•    The movie «Zenith» is going to win several Academy Awards.