German Phrase
Wie alt bist du?
Meaning
This phrase is the standard informal way to ask someone their age in German. Unlike some other languages that use the verb 'to have' for age, German uses the verb 'sein' (to be). It is a direct and common question in casual social settings.
When to use
Use this phrase when speaking to friends, children, or people your own age in informal contexts. It is the 'du' form, so it implies a level of familiarity or a casual atmosphere.
✦Grammar Breakdown
Wiealtbistdu
Wie
An interrogative adverb meaning 'how', used here to quantify the adjective 'alt'.
bist
The informal second-person singular conjugation of the irregular verb 'sein' (to be).
🗨In Conversation
Ich habe heute Geburtstag!
It's my birthday today!
Echt? Wie alt bist du?
Really? How old are you?
✕Common Mistakes
Wie alt hast du?
German uses the verb 'sein' (to be) for age, not 'haben' (to have).
Wie alt bist Sie?
The verb 'bist' must match the pronoun 'du'. For 'Sie', use 'sind'.
↔Alternatives
Wie alt sind Sie?
How old are you? (Formal)
Welches Baujahr bist du?
What year were you born? (Slang/Informal)
Cultural Tip
In German-speaking countries, asking an adult's age can sometimes be considered impolite if you aren't close. However, it is a standard question for children and very common among teenagers or university students. When in doubt in a professional setting, it is better to avoid the question entirely.