Explanation

Sein (to be) and haben (to have) are the two most important verbs in German. Both are fully irregular and must be memorised. They are also the auxiliary verbs used to form the past tense (Perfekt).

Rules

sein (to be):

PersonForm
ichbin
dubist
er/sie/esist
wirsind
ihrseid
sie/Siesind

haben (to have):

PersonForm
ichhabe
duhast
er/sie/eshat
wirhaben
ihrhabt
sie/Siehaben

Examples

Sein:

  • Ich bin Student. — I am a student.
  • Er ist müde. — He is tired.
  • Wir sind in Berlin. — We are in Berlin.
  • Wie alt bist du? — How old are you?

Haben:

  • Ich habe einen Hund. — I have a dog.
  • Sie hat keine Zeit. — She has no time.
  • Wir haben Hunger. — We are hungry. (lit. we have hunger)

Exceptions

Many common German expressions use haben where English uses to be:

  • Hunger haben — to be hungry
  • Durst haben — to be thirsty
  • Angst haben — to be afraid
  • Recht haben — to be right

Notes

Both verbs are used as auxiliaries to form the perfect past tense. Most verbs use haben; verbs of movement/change of state use sein (e.g. gehen → ich bin gegangen).