The Perfekt is a compound past tense in German that is used in everyday conversation to talk about completed actions. Most verbs form the Perfekt with the auxiliary verb haben combined with a past participle. For regular (weak) verbs, the past participle follows a clear pattern: ge- plus the verb stem plus -t. For example, machen becomes gemacht, so you would say Ich habe es gemacht to mean I have done it. Similarly, spielen becomes gespielt, lernen becomes gelernt, arbeiten becomes gearbeitet, kaufen becomes gekauft, and kochen becomes gekocht. A complete sentence might be Sie hat Deutsch gelernt to say She learned German, or Meine Mutter hat Suppe gekocht for My mother cooked soup. This ge- + stem + -t pattern is the foundation of regular Perfekt formation.
Irregular (strong) verbs follow a different pattern. Their past participles often involve a stem vowel change and end in -en rather than -t. The verb essen (to eat) becomes gegessen, as in Ich habe Pizza gegessen (I ate pizza). Trinken becomes getrunken, so Er hat Kaffee getrunken means He drank coffee. Schreiben becomes geschrieben, lesen becomes gelesen, and sehen becomes gesehen. Other common irregular verbs include nehmen, which becomes genommen (Er hat den Bus genommen — He took the bus), finden, which becomes gefunden (Hast du deinen Schlüssel gefunden? — Did you find your key?), and sprechen, which becomes gesprochen (Ich habe mit ihm gesprochen — I spoke with him). Even though the past participles themselves are irregular, the auxiliary verb haben is still used in all of these examples.
To use the Perfekt in a complete sentence, place the auxiliary haben in second position and send the past participle to the end of the clause. For example, Ich habe gestern Klavier gespielt means I played piano yesterday, where spielen becomes gespielt and is placed at the end of the sentence. The Perfekt can describe both recent and distant past events, and it is the most common spoken past tense in modern German, used alongside the simple past Präteritum which appears more often in written narratives.