For verbs, the past participle is formed by starting with the infinitive, removing the -ar, -er, or -ir, and adding -ado for -ar verbs and -ido for -er and -ir verbs. For example:

Note that -er and -ir verbs with stems ending in a vowel add an accent over the i of the ending:

As one might expect, there are some irregular forms of the past participle. Here is a list of the most common verbs with irregular past participles:

That's all there is to forming the past participle.

One uses the past participle in two different ways, either as an adjective (She is prepared: Ella está preparada.) or as part of the present perfect (and other compound tenses): She has done the homework: Ella ha hecho la tarea. When the participle is used as an adjective, it functions as an adjective and agrees with its subject::

El chico está preparado.
La chica está preparada.
Los chicos están preparados.
Las chicas están preparadas.

On the other hand, when used as part of the present perfect tense, the participle always ends in an -o:

El chico ha hecho la tarea.
La chica ha hecho la tarea.
Los chicos han hecho la tarea.
Las chicas han hecho la tarea.

For practice on forming the past participle, click on the following link:

Past (perfect) participle