Main points

* When you are making predictions about the future or talking about future intentions, you can use either `will’ (`I will walk’) or `going to’ (`I am going to walk’).

* For promises and offers relating to the future, you use `will’ (`I will walk’).

* For future events based on arrangements, you use the future continuous (`I will be walking’).

* For events that will happen before a time in the future, you use the future perfect (`I will have walked’).

1 You cannot talk about the future with as much certainty as you can about the present or the past. You are usually talking about what you think might happen or what you intend to happen. This is why you often use modals. Although most modals can be used with future reference, you most often use the modal `will’ to talk about the future.
Nancy will arrange it.
When will I see them?

2 When you are making predictions about the future that are based on general beliefs, opinions, or attitudes, you use `will’.
The weather tomorrow will be warm and sunny.
I’m sure you will enjoy your visit to the zoo.

This use of `will’ is common in sentences with conditional clauses.
You’ll be late, if you don’t hurry.

When you are using facts or events in the present situation as evidence for a prediction, you can use `going to’.
It’s going to rain . (I can see black clouds)
I’m going to be late. (I have missed my train)

3 When you are saying what someone has decided to do, you use `going to’.
They’re going to have a party.
I’m going to stay at home today.

WARNING: You do not normally use `going to’ with the verb `go’. You usually just say `I’m going’ rather than `I’m going to go’.

`What are you going to do this weekend?’ – `I’m going to the cinema.’

When you are announcing a decision you have just made or are about to make, you use `will’.
I’m tired. I think I’ll go to bed.

4 In promises and offers relating to the future, you often use `will’ with the meaning `be willing to’.
I’ll do what I can.
I’ll help with the washing-up.

Note that you can use `will’ with this meaning in an `if’-clause.
I’ll put you through, if you’ll hang on for a minute. (= if you are willing to hang on for a minute)

WARNING: Remember that you do not normally use `will’ in `if’-clauses.
See Unit 66 for more information on `if’-clauses.

If you do that, you will be wasting your time.
The children will call out if they think he is wrong.

5 When you want to say that something will happen because arrangements have been made, you use the future continuous tense.
I’ll be seeing them when I’ve finished with you.
I’ll be waiting for you outside.
She’ll be appearing at the Royal Festival Hall.

6 When you want to talk about something that has not happened yet but will happen before a particular time in the future, you use the future perfect tense.
By the time we phone he’ll already have started.
By 2010, he will have worked for twelve years.