Overview of the Spanish Conditional Perfect:

The conditional perfect is used to describe events that would have happened under certain cirumstances, e.g.: 

• Ya habríamos salido pero tuvimos que esperar a mi hermana. ("We would've left already but we had to wait for my sister.")
• Si tuviera suficiente dinero, habría comprado un coche ("If I had enough money, I would have bought a car.").

As this example illustrates, the conditional perfect describes a past action that did not happened since the condition in the subordinate clause (starting with subordinate conjunction si) of the sentence (having enough money) was not met. The conditional perfect is the form used to mean "could have", "would have" and "should have" in Spanish.

Like the present conditional, the conditional perfect should NOT be used immediately after the word si; rather, use the imperfect subjunctive after si in the subordinate clause and the conditional perfect in the main clause, e.g.: Habría ido contigo al cine si no fuera por mi examen mañana.

How to form the Conditional Perfect

The past conditional is formed by using the present conditional of haber, followed by the past participle. This is illustrated in the following table: