When & if in German (als/wann/wenn/ob)

The German translations of when and if can pose difficulties or confusion to language learners. Knowing how to differentiate and use them in the right circumstances is important to speaking without misunderstanding.

If: wenn or ob?

When translated, wenn and ob in subordinating conjunctions are used in completely different situations.
  • Wenn is used in the conditional, introducing a requirement or condition.
    • Wenn du willst, können wir früher essen. (If you want, we can eat earlier.)
  • Ob is used in the indirect interrogative, or when the answer could be yes or no.
    • Ich weiß nicht, ob er kommt. (I do not know if he is coming.)

When: wenn or wann?

The spelling difference between wenn and wann is subtle, as well as its difference in usage. Their meaning is the same, but situational use is different.
  • Wenn is for the case in which when means a repetition. It can replace "every time" in a sentence.
    • Wenn wir arbeiten, hören wir gern Musik. (When we work, we like to listen to music.)
  • Wann refers to a specific time, and is used as an interrogative pronoun.
    • Wann ist der Termin? (When is the meeting?)
    • Kommt, wann ihr wollt. (Come when you want.)

When: als or wenn?

  • Als is a conjunction that introduces an event from the past, which is not repeated. It is generally followed by the preterit.
    • Als sie ein Kind war, lernte sie Klavier spielen. (When she was a child, she learned to play the piano.)
  • Wenn is a conjunction that translates as when and is used for events that happen repeatedly. It can be easily replaced by "every time".
    • Wenn mein Vater gelesen hat, hat er im Sessel gesessen.
    • When my father read, he would sit in the armchair.
  • Wenn is also used for unique events to come.
    • Wenn du damit fertig bist, kannst du runter kommen.
    • When you are done with it, you can come down.