The same twelve common verbs that are irregular in the future tense are also irregular in the conditional tense. Their endings are regular, but their stems change in the same way they change in the future tense. Because the endings are the same as all other conditional tense verbs, only the yoform is shown here:
caber yo cabría I would fit poner yo pondría I would put decir yo diría I would say haber yo habría I would have [done/been…] salir yo saldría I would have gone out hacer yo haría I would have done/made poder yo podría I would have been able tener yo tendría I would have had querer yo querría I would have wanted valer yo valdría I would have been worth saber yo sabría I would have known venir yo vendría I would have come
¿Cuándo se usa el condicional?
The conditional is used to express probability, possibility, wonder or conjecture. It is usually translated as would, could, must have or probably.
She said that she would study one more hour. Ella dijo que estudiaría una hora más.
What time could it be? ¿Qué hora sería?
He must be at home. Estaría en su casa.
I would like to learn Spanish. Me gustaría aprender el español.
One very important usage of the conditional is for softening polite requests:
¿Por favor, podría decirme a qué hora abre la gasolinera? Please, could you tell me what time the gas station opens?