Do you know Spanish Future Tense (Futuro Simple)?
Yo iré, comeré, trabajaré...
Tú irás, comerás, trabajarás...
And now... Surprise!!! In the modern Spanish language this tense called "future" (Futuro), is not frequently used to refer to future. The future verb forms are mainly used to indicate probability, to express guesses and not only about future but about present as well. In English such an idea can be conveyed by using expressions like "probably," "likely," "I suppose", modal verbs of probability or similar words or expressions. Thus, the phrase
María estará trabajando ahora
doesn't refer to future. It means "I suppose María is working right now.".
This tense (Futuro) always indicates probability or likelihood even if the phrase refers to future. The sentense
El año que viene estaré trabajando
is not neutral. It means something like: "I'm not sure what my plans are for next year. I might work.".
Futuro Simple is used as Future Tense only in two cases: in official news and in emotional speech:
(moticias) Mañana vendrá una delegación = (lenguaje coloquial) Mañana viene una delegación
(emoción fuerte) ¡Nunca serás mi pareja!
Now, a logical question arises: how to express "usual" future, not indicating anything else but future? There are two ways to do that:
- If you are sure that an event is to take place in future, that is, you perceive it as "an accomplished fact", you must use Presente instead of Futuro (Future Tense):
Mañana vienen mis padres.
Esta noche ceno con mi novia.
El año que viene acabo la carrera.
- If you're not quite sure, but the the action/event has been arranged, you must use ir a + infinitivo:
Mañana van a venir mis padres
Esta noche voy a cenar con mi novia
El año que viene voy a terminar la carrera
All these phrases express simple future facts/arrangements without any additional meanings:
My parents are coming tomorrow. I'm having dinner with my girlfriend this evening. I'll graduate next year.
Pay attention to the English translation: in Spanish we never use estar + gerundio (analog of Present Continuous) in order to express future.
In terms of statistics, the ir a + infinitivo form is the most common way to refer to (arranged) future. It does not refer to "intentions". Voy a terminar la carrera means "I'll graduate". And remember, never use Future Tense speaking of the present moment:
CORRECTO: Ahora voy al mercado
INCORRECTO: Ahora *iréal mercado