German car number plates show the place where the car carrying them is registered. Whenever a person changes their main place of residence in Germany, or buys a new car, they are required to buy new number plates. Number plates can be bought which are valid all year round or between 2 to 11 months within any 12 months. This allows to change between summer and winter cars, such as a convertible and a sedan/saloon without having the time and money wasted for de- and re-registering. Emission test (front plate) and vehicle safety test (rear plate) stickers are also attached to the plate. The expiry date can be figured out as following: The year is in the centre of the sticker and the number on the uppermost is the month. The black marking on the side makes it easy for the police to see the expiring month from the distance. Imagine a clock, then the the marking shows the same position as the face of the clock does. For example the black marking is on the left side, so it is the ninth month (or 9 o'clock) and hence the expiry date is 30th September. The colours are repeated every 6 years. The lower sticker is the official "seal" of registration — indeed, at the beginning of the 20th century, plates were authorised with ink and a stamp. Motorcycles carry only the rear plate.

The post-1994 German number plate format
The present number plate format, used since 1994, uses black print on a white background and first provides information about the country where the car is registered, in the form of a D (for Deutschland) on the blue strip on the left, like many European Union number plates.

After that, there are between one and three letters which show the city or region where the car is registered. DD stands for Dresden, D for Düsseldorf and MST for Mecklenburg-Strelitz, for example. These units usually coincide with the German districts, in few cases an urban district and the surrounding district share the same letter code. Hanseatic cities may have an H in front of them, e.g. HH for Hansestadt Hamburg or HRO for Hansestadt Rostock. The number of letters in the city/region prefix often reflects the size of the city: one letter for a large city (B= Berlin or H=Hannover) two for a medium-sized city (DD= Dresden) or three for a small city (MST=Mecklenburg-Strelitz).

After the location name come the emission test and vehicle safety test stickers, then one or two usually random letters followed by one to four usually random numbers. The total quantity of letters and numbers on the plate is never higher than eight. One letter with low numbers are normally reserved for motorcycle use since the plates space of this vehicles is smaller.

Car owners can personalise their plates by choosing certain numbers or letters instead of the random ones at the end. For example, people living in the town of Pirna might choose PIR-AT 77, "Pirat" being the German for "pirate"; another favourite is BAR-BQ 777 for Barnim. Various combinations that could be considered politically unacceptable — mainly due to implications relating to Nazi Germany — are disallowed or otherwise avoided. The district Sächsische Schweiz uses the name of its main town, Pirna, in its code PIR, to avoid the use of SS, the name of the paramilitary organisation; similarly SA is also avoided. In 2004 in Nuremberg, a car owner was refused a number plate beginning N-PD because of the connection to the political party, the NPD.

Example of banned combination ("NS") which has been issued accidentally.Other banned combinations include the Nazi abbreviations HJ (Hitlerjugend, Hitler Youth), NS (Nationalsozialismus, National Socialism), SA (Sturmabteilung), SS (Schutzstaffel) and KZ (Konzentrationslager, concentration camp). Some registration offices have overlooked this rule by mistake, however; there are a few cars registered carrying prohibited codes, such as B-SS 12.

Certain types of vehicle bear special codes:

Vintage cars (known in German by the pseudo-English expression Oldtimer) have an H (historic) at the end of the plate, such as K-AA 100H

Cars with seasonal number plates have two numbers at the end of the plate indicating the months between which they are registered to drive, with the licence being valid from the start of the upper month until the end of the lower month.

Official cars such as police, fire fighting and municipality vehicles do not carry a letter after the sticker, such as M-1234. Police cars usually start with the number 3, example: S-3123

Until 2004, vehicles which do not have to pay the usual taxes (for example ambulances, tractors or trailer for boats) were green print on a white background.

Vehicles which have not been registered (because they are being repaired, for example) have to carry short-term plates valid only for five days. The code starts with the numbers 04, e.g. DD-04000, and the plate has a yellow strip on the right showing when they are valid. The date is listed numerically, on three lines, reading day, month, year, with two digits each.

Car dealers' plates are in red print on a white background, and the code begins with 06.

Diplomatic plates have the digit 0 (Zero) on the left instead of the registration location code.

The military uses old style non-reflecting plates with a dash between the two circles. The German flag is shown, instead of the blue EU strip. Military plates use the letter Y, rather than a city indicator (no large German city name starts with a Y). After the Y comes a six-digit number (or five digits for motorcycles), for example Y-123456

Military vehicles which are used by the Nato headquarters in Germany use the same design as the Y-plates except they carry the letter X followed by a four-digit number, for example X-1234

Some branches of the federal government and Bundesländer's governments use the abbreviations of their names instead of a city code. Example: the Technisches Hilfswerk (German Federal Agency for Technical Relief) uses its abbreviation THW, so the plates read like THW-12345

The federal border police (Bundesgrenzschutz) uses the code BG (BG-#####) instead of the local code.