El futuro
(Future tense)

Spanish, like English, employs various constructions to talk about the future. For instance, it is common to use the present tense to talk about the near future:

Mañana salgo para Madrid = Tomorrow I leave for Madrid

Another common Spanish construction to express the future is ir + a + infinitive, which is parallel to English "to be going" + infinitive:

Vamos a comer en casa esta noche = We are going to eat at home tonight.

The ir + a + infinitive construction is the most common way of expressing the future in spoken Spanish. However, there is also a more formal way of talking about the future, somewhat equivalent to the English future with "will". While this more formal future construction is not as common in spoken Spanish, it is very common in written language, and in more formal speech. This form of the future is sometimes called the futuro simple because it is formed with one word rather than a sequence of words. The futuro simple of regular verbs is formed by adding the appropriate endings onto the infinitive; there is no difference between -ar, -er, and -ir endings:

daré daremos leeré leeremos iré iremos
darás daréis leerás leeréis irás iréis
dará darán leerá leerán irá irán

There are a dozen or so irregular verbs in the futuro simple; they fall into 3 principle categories:

1. Verbs that drop the last vowel of the infinitive: caber, haber, poder, querer, saber

poder > podr- podré podremos
  podrás podréis
  podrá podrán

2. Verbs that drop two letters of the infinitive: decir, hacer

decir > dir- diré diremos
  dirás diréis
  dirá dirán

3. Verbs that drop the last vowel of the infinitive and insert a d: poner, salir, tener, valer, venir

tener > tendr- tendré tendremos
  tendrás tendréis
  tendrá tendrán