The Future tense

1. Predictions/statements of fact

2. Intentions
3. Arrangements
4. Scheduled events

Predictions/statements of fact

The auxiliary verb will is used in making predictions or simple statements of fact about the future.

• The sun will rise at 6.30 tomorrow.
• Lunch break today will be 10 minutes longer than usual.
• In the year 2050 all students will have their own computers in school.
• If you help me, I will help you.
• Do you think she will come soon?
• You won't pass your exams if you don't start working harder.
• I know my parents won't let me go to the party.
• Will it snow for Christmas?
• I know she's sick, but will she be back in school tomorrow?

Intentions

The auxiliary verb going to is used in talking about intentions. (An intention is a plan for the future that you have already thought about.)

• We're going to buy a new car next month.
• I'm going to work in a bank when I leave school.
• In the new year I'm going to stop eating so much junk.
• He's not going to go to the dance. He's got too much work.
• I'm not going to watch TV until my science project is finished.
• Are you going to play basketball after school?
• What are you going to have for lunch today?

Note: going to is often used in the past tense to talk about an unfulfilled intention. Examples: I was going to study for my grammar test, but I had no time. / He was going to call you, but he couldn't find his mobile phone. / My grandmother was going to visit us, but she fell and broke her arm.

Arrangements

The present continuous tense is used in talking about arrangements. (An arrangement is is a plan for the future that you have already thought about and discussed with someone else.)

• I'm meeting my mother at the airport tomorrow.
• Our grandparents are visiting us this Christmas.
• Sorry, I can't stay after school today; I'm playing tennis with Jun-Sik.
• My sister's going to the dentist tomorrow.
• I'm not returning home for the holidays, so I can come to your party after all!
• Are you doing anything on Sunday morning?
• Do you know if he is going to the dance with Maiko next week?

Scheduled events

The present simple tense is usually used to refer to future events that are scheduled (and outside of our control).

• Hurry up! The train departs in 10 minutes.
• I leave Frankfurt at 5 o'clock in the morning and arrive in New York
at midnight the next day.
• She has an appointment with the headmaster after school today.
• There's no need to hurry. The train doesn't leave for another 30 minutes.
• When does the meeting begin?

Source:
http://esl.fis.edu/grammar/rules/future.htm