From Hull AWE
In strict terms English does not have a future tense: it only has two tenses marked by inflection, present and past. Instead, there are several ways to construct a verb phrase to speak of an action in the future.
- With modal verbs such as 'shall', 'will' or 'going to': "I will go to Italy next year." Whether shall or will is used reflects on the speaker's attitude to the event.
- With the present tense, usually in the progressive aspect: "I am going to the cinema tonight." (This is further evidence of the fact that language is not logical!)
- Combining a modal verb with the present tense in the perfect aspect, we can speak of actions will eventually be in that past: "I will have seen the doctor on Monday." ("I am seeing the doctor in the future, but I am thinking of a time further in the future than that, when seeing the doctor will be in the past." If you think that's complicated, try the fictional tenses Douglas Adams invents to described time travel in The Restaurant at the End of the Universe.)