German Du vs Sie — Formal and Informal Address Rules

German has two forms of "you": du (informal, lowercase) and Sie (formal, always capitalized). Use Sie with strangers, people older than you, authority figures, customers, and in business settings. Use du with friends, family, children, students, and in casual settings (gyms, youth culture, online). The transition from Sie to du is called "das Duzen" and is always initiated by the older or higher-status person. Never assume du with a German adult you've just met.