Dutch Postcodes Format
Dutch Postcode consists of four digits one space followed by two uppercase letters. The letter combinations 'SS', 'SD' and 'SA' are not used because of historical reasons. Until 2005 the letters 'F', 'I', 'O', 'Q', 'U' and 'Y' were not used for technical reasons. The first two digits of the postcode indicate a city and a region. The following two digits and letters indicate a range of house numbers usually on the same street. A Dutch postcode in average covers eight single addresses. So a postal address is uniquely defined by the postcode and the house number.
The system was introduced in 1976. Unlike many European countries, Netherlands do not use a country prefix. The borders of postcode areas do not match well with province borders.