Postal codes in Germany
introduced postal codes on 25 July 1941, in the form of a two-digit system that was applied initially for the parcel service and later for all mail deliveries. This system was replaced in 1962 in West Germany by a four-digit system; three years later East Germany followed with its own four-digit system. Whereas the Federal Republic introduced a system with space left for the East German postal system after a possible reunification, such as by omitting all codes starting with '1' and '9', the German Democratic Republic had a system that used all codes starting from '1' to '9' just for East Germany.
Today, German postal codes are numeric, consisting of five digits since 1993. Between 1990 and 1993 the old four-digit codes in the former West were prefixed with the letter "W", and in the former East with the letter "O". Even though the western system had kept some number ranges free specifically for later integration of the East should reunification come, it was decided that the time was right to create an entirely new system in the 1990s, in which larger towns and cities would be divided into multiple postal code areas, and companies receiving a lot of mail could get a private code assigned. This resulted in a system where one could no longer identify the size of the city by the number of trailing zeros in its postal code.
Post office boxes are arranged in racks containing several dozens of them. Each rack is identified by an individual postal code.
The 1993 system has geographic zones on the first and on the second level, e.g., 1 is North East Germany, and 10 is a zone in the inner city of Berlin.
As of 31 December, 2007, the zones have the following area and population:
| Leitzone | Area | Population | Region covered | Large cities |
| 0 | 37,187.8 | 6,819,607 | Saxony, southern parts of Saxony-Anhalt and Brandenburg, eastern parts of Thuringia | Dresden, Leipzig, Halle, Chemnitz, Cottbus, Jena |
| 1 | 47,642.4 | 7,034,541 | Berlin, largest parts of Brandenburg and Mecklenburg-Vorpommern, small parts of Lower Saxony and Saxony-Anhalt | Berlin, Potsdam, Frankfurt, Rostock, Schwerin |
| 2 | 44,207.4 | 8,691,409 | Hamburg, Schleswig-Holstein, northern parts of Lower Saxony, Bremen, small parts of Mecklenburg-Vorpommern | Hamburg, Lübeck, Kiel, Bremen, Bremerhaven, Oldenburg |
| 3 | 45,488.1 | 9,012,212 | southern parts of Lower Saxony, eastern parts of Westphalia, northern parts of Hesse, Thuringia and Saxony-Anhalt | Hanover, Bielefeld, Kassel, Fulda, Gießen, Göttingen, Brunswick, Magdeburg |
| 4 | 20,212.3 | 10,331,535 | north-western parts of North Rhine-Westphalia, south-western parts of Lower Saxony | Düsseldorf, Dortmund, Essen, Duisburg, Münster, Osnabrück |
| 5 | 28,834.5 | 9,233,815 | south-western parts of North Rhine-Westphalia, largest parts of Rhineland-Palatinate, small parts of Hesse | Cologne, Bonn, Aachen, Mainz, Koblenz, Trier |
| 6 | 17,247.9 | 7,540,503 | southern parts of Hesse, Rhineland-Palatinate, Saarland, small parts of Bavaria and Baden-Württemberg | Frankfurt, Wiesbaden, Darmstadt, Saarbrücken, Heidelberg, Mannheim, Aschaffenburg |
| 7 | 27,864.2 | 8,715,898 | largest parts of Baden-Württemberg, small parts of Rhineland-Palatinate | Stuttgart, Tübingen, Freiburg, Konstanz, Baden-Baden |
| 8 | 36,427.2 | 7,675,001 | southern parts of Bavaria, south-eastern parts of Baden-Württemberg | Munich, Rosenheim, Augsburg, Ulm, Ingolstadt |
| 9 | 47,803.7 | 7,163,416 | northern parts of Bavaria, largest parts of Thuringia, small parts of Baden-Württemberg | Nuremberg, Würzburg, Erfurt, Weimar, Eisenach, Bamberg, Bayreuth |
There are three states, in addition to the city states, that lie completely within one postal zone, while three states cover four postal zones.