Post Office

Post offices in larger towns and cities are generally open Monday to Friday from 8am to 6pm, and on Saturdays until midday. At larger railway stations and airports they often stay open for longer and also open on Sundays.
Street mailboxes are painted yellow. Pickup times are listed on the box.
Mail General delivery, mark it POSTE RESTANTE, can be used in any major town or city in Germany. You can pick up your mail upon presentation of a valid identity card or passport.
German postal codes (Postleitzahlen) are five-digit numbers. It costs €0.55 ($0.74 ) to mail a standard letter weighing up to 20 grams within Germany and € 0.70 for other European countries.
A standard overseas letter costs €1.70.
Postcards cost €0.45 within Germany and €1 abroad.