German marks what a word is doing in the sentence by changing the article in front of it. The nominative marks the subject — the one performing the action. The accusative marks the direct object — the person or thing the action lands on. English does this with word order alone; German does it with the article, which is why the article has to change.
The one question that decides it
You never have to guess. Ask the verb two questions. Wer? (who is doing it?) finds the nominative. Wen? or Was? (whom or what is it happening to?) finds the accusative. Whatever answers wer? stays nominative; whatever answers wen? goes accusative.
Der Hund beißt den Mann.
The dog bites the man.
Wer beißt? → der Hund (nominative). Wen beißt er? → den Mann (accusative).
Der Mann beißt den Hund.
The man bites the dog.
Swap the articles and you swap who is doing what.
Die Frau sieht das Kind.
The woman sees the child.
Feminine and neuter look identical in both cases — nothing visibly changes.
Only the masculine actually changes
This is the part that makes it manageable. Of the four article forms, exactly one looks different in the accusative: masculine der becomes den, and ein becomes einen. Feminine, neuter and plural are identical to the nominative, so three quarters of the time there is nothing to do.
| Gender | Nominative | Accusative |
|---|---|---|
| Masculine | der / ein Mann | den / einen Mann |
| Feminine | die / eine Frau | die / eine Frau |
| Neuter | das / ein Kind | das / ein Kind |
| Plural | die Kinder | die Kinder |
Pronouns change far more visibly than articles do — ich becomes mich, du becomes dich, er becomes ihn. The full table lives in the personal pronouns guide; the wer/wen test picks the right column there too.
Word order does not decide the case
This trips up English speakers hardest. In English, the first noun is the subject — that is the only signal you have. In German the article carries the role, so the object can move to the front for emphasis and the meaning does not change at all.
Ich sehe den Hund.
I see the dog.
Normal order.
Den Hund sehe ich.
The dog, I see.
Object first for emphasis — but den still marks it as the object, so the meaning is identical.
The verbs that keep the nominative
A small group of verbs does not take an object at all. With sein, werden and bleiben, the thing after the verb is another description of the subject, so it stays nominative. This is the single most common place learners over-apply the accusative.
Er ist ein guter Lehrer.
He is a good teacher.
sein → nominative. Not einen.
Sie wird eine gute Ärztin.
She is becoming a good doctor.
werden → nominative.
Das bleibt ein Problem.
That remains a problem.
bleiben → nominative.
Prepositions that force the accusative
Five common prepositions always take the accusative, no matter the meaning — the wer/wen test does not apply after them, the preposition simply decides. A classic memory hook is “durch, für, gegen, ohne, um.”
Wir gehen durch den Park.
We walk through the park.
durch → den
Das Geschenk ist für dich.
The gift is for you.
für → accusative pronoun dich
Ich habe nichts gegen ihn.
I have nothing against him.
gegen → ihn
Sie kommt ohne einen Mantel.
She comes without a coat.
ohne → einen
Wir sitzen um den Tisch.
We sit around the table.
um → den
✗Ich sehe der Hund.
✓Ich sehe den Hund.
Wen sehe ich? → the dog is the object, and masculine objects take den.
✗Den Hund ist groß.
✓Der Hund ist groß.
Here the dog is doing the being, not receiving anything — wer ist groß? → nominative.
✗Er ist einen guter Lehrer.
✓Er ist ein guter Lehrer.
sein never takes an object, so the nominative stays.
✗Ein Geschenk für du.
✓Ein Geschenk für dich.
für takes the accusative, so du → dich.
Tipp · Before you pick an article, say the verb and ask wer? then wen?. If the answer is the one doing it, nothing changes. If it is the one being acted on and the noun is masculine, that is your der → den. Everything else in the system is built on that one swap.