In Europe the most common house numbering scheme, in this article referred to as the "European" scheme, is to number each plot on one side of the road with ascending odd numbers, from 1, and those on the other with ascending even numbers, from 2 (or sometimes 0). The odd numbers are usually on the left side of the road, looking in the direction in which the numbers increase. Where additional buildings are inserted or subdivided, these are often suffixed a, b, c, etc. (in Spain, France and
Afragola until 2001,
bis,
ter,
quater,
quinquies etc.). Where buildings are later combined, one of the original numbers may be used, the numbers may be combined ("13/15"), or the numbers may be used as a given range (e.g. "13–17"; not to be construed as including the even numbers 14 and 16). Buildings with multiple entrances may have a single number for the entire building or a separate number for each entrance. Where plots are not built upon gaps may be left in the numbering scheme or marked on maps for the plots. If buildings are added to a stretch of old street the following may be used rather than a long series of suffixes to the existing numbers: a new name for a new estate/block along the street (e.g.
1–100 Waterloo Place/Platz, Sud St.); a new road name inserted along the course of a street either with or without mention of the parent street; unused numbers
above the highest house number may be used (although rarely as this introduces confusing discontinuity), or the upper remainder of the street is renumbered. Other local numbering schemes are also in use for administrative or historic reasons, including clockwise and anti-clockwise numbering, district-based numbering, distance-based numbering, and double numbering.
France The first record of a house numbering system in
Paris dates to the 15th century. On March 1, 1768, King
Louis XV decreed that all houses outside of Paris were to be assigned a number to help locate the soldiers residing in civilian houses. On February 4, 1805,
Napoleon I announced that in Paris for house numbering a distinction should be made between even numbers (on the right side) and odd numbers (on the left side); the direction of the streets is oriented from upstream to downstream for streets parallel to the
Seine, and from the banks to the north and south for streets oblique or perpendicular to the Seine. Such a system quickly became common in large cities across France. A ruling in 1994 obliged French communes with a population of 2,000 or more to number their houses. Sequential numbering, common in cities, mimics the system used in Paris. But many small villages used the numbering which takes a central village point — often the town hall — and works outward (a house that is 200 metres along the road from point zero will be numbered 200, its nearest neighbour, perhaps 270 metres from the centre, becomes number 270, etc.)
Finland The Finnish numbering system incorporates solutions to the problems which arose with mass urbanization and increase in building density. Addresses always are formatted as street name followed by street address number. With new,
infill building, new addresses are created by adding letters representing the new ground level access point within the old street address, and if there are more apartments than ground level access points, a number added for the apartment number within the new development. The original street numbering system followed the pattern of odd numbers on one side and even numbers on the other side of the street, with lower numbers towards the center of town and higher numbers further away from the center. The infill numbering system avoids renumbering the entire street when developments are modified. For example, Mannerheimintie 5 (a large mansion house on a large city plot) was demolished and replaced with 4 new buildings each with 2 stairwells all accessible from Mannerheimintie. The 8 new access stairwells are labelled A B C D E F G and H (each with the letter visible above the stairwell). Each stairwell has 4 apartments on 5 floors, so the new development has 160 new addresses in all running from Mannerheimintie 5 A 1 through to Mannerheimintie 5 H 160. The opposite example is where old, narrow buildings have been combined; Iso Roobertinkatu 36, 38 and 40 were demolished in the 1920s and the new building has the address Iso Roobertinkatu 36–40. In the rural parts of Finland, a variant of this method is used. As in towns, odd and even numbers are on opposite sides of the road, but many numbers are skipped. Instead, the house number indicates the distance in tens of metres from the start of the road. For example, "Pengertie 159" would be 1590 metres from the place where Pengertie starts.
Netherlands When more buildings are constructed than numbers were originally allotted, discontinuity of numbering is avoided by giving multiple adjacent buildings the same number, with a letter suffix starting at "A". The "Bis" suffix is used occasionally. Each house or apartment can be uniquely identified by a combination of a postcode, a street number and a suffix. Apartments within the same building can be distinguished various ways: by assigning each apartment their own street number, by assigning a simple prefix (generally a letter) or by assigning a complex prefix that takes into account both the floor and the apartment on the floor (e.g. B3). In
Haarlem, Netherlands, red numbers are used for upstairs apartments.
Portugal In Portugal, the European scheme is most commonly used. However, in
Porto and several other cities in the Portuguese
Northern region, as well as in the
Cascais Municipality (near
Lisbon), houses are numbered in the North American style, with the number assigned being proportional to the distance in meters from the baseline of the street.
Lisbon numbering is European and furthermore 'from the river, odd numbers left'. Because the
Tagus borders Lisbon on the south and the east, this means that north–south streets are numbered low from the south, and east–west streets are numbered low from the east. In many new planned neighborhoods of Portugal houses and other buildings are identified by a
lote (plot) number without reference to their street. This is in law the
número de polícia, which literally means ''police's number
– the police formerly assigned the numbers rather than the town hall. The lote
is the construction plot number used in the urban plan, a consecutive number series applies to a broad neighborhood. In theory and in most cases, the use of a lote
number system is provisional, being replaced by a traditional street number system some time after the neighborhood is built and inhabited. In some neighborhoods, lote'' numbers are kept for many years, some never being replaced by street numbers. The relatively new planned neighborhood of
Parque das Nações in Lisbon has also a different numbering scheme: each building is referred by its plot, parcel, and building (in Portuguese:
lote,
parcela,
prédio).
United Kingdom The European system is most widely used. The odd numbers will typically be on the left-hand side as seen in the direction of increasing numbers (most commonly with the lowest numbers at the end of the street closest to the town or village centre). Intermediate properties usually have a number suffixed A, B, C, etc., much more rarely instead being given a half number, e.g. the old police station at Camberwell Church Street. It is extremely rare for a property (built next to no. 2 after the street had been numbered) to be zero (0) or named Minusone; in 2013 researchers found these instances once in
Middlesbrough and once in
Newbury. In 2022, starting to type "0," into the Royal Mail postcode search revealed Middlesbrough had four listed properties, whilst Birmingham, Ellesmere Port, Lincoln and London have one each. In many rural streets, significantly built alongside before 1900, houses remain named and unnumbered. In some places, particularly when open land, a river or a large church fronts one side, all plots on one side of a street are numbered consecutively. Such a street if modern and long is more likely to be numbered using odd numbers, starting at 1. Along oldest streets, numbering is usually clockwise and consecutive: for example in
Pall Mall, some
new towns, and in many villages in Wales. This often also applies to
culs-de-sac and standalone
terraces. For instance,
10 Downing Street, the official home of the
Prime Minister, is next door to
11 Downing Street. Houses which surround squares, as well as market places, are usually numbered consecutively clockwise. In the early to mid 19th century numbering of long urban streets commonly changed from clockwise (strict consecutive) to odds facing evens, particularly when roads were extended into new suburbs. Where this took place it presents a street-long pitfall to researchers using historic
street directories and other records. A very rare variation may be seen where a
high street (main street) continues from a less commercial part – a road which breaks the UK conventions by not starting at 1 or 2. On one side of the main road between Stratford and Leytonstone houses up to no. 122 are "Leytonstone Road". The next house is "124 High Road, Leytonstone". In some villages, a single numbering system covers the entire settlement, especially in rural areas without formal street names. In this case the house number directly precedes the village name in addresses. This often coexists with newer developments within the same village that use street names (e.g., "58 Dorfield" alongside "3 Church Close, Dorfield"), although to avoid confusion the older houses may eventually gain street names of their own while keeping their numbers ("58 Axtley Road, Dorfield"). Developers may avoid the number 13 for house numbering as in Iran, because that number is
considered by some to be unlucky. Blocks of flats (apartments) are treated in two ways: • Flats numbered individually as part of the street. A
lintel will typically be embossed or metalled "1–24 Acacia Avenue" or "Flats 1–24 Acacia Avenue". • Flats numbered within a building. The building retains its own number (or name) on the street e.g. "Flat 24, 1 Acacia Avenue" or increasingly as commonly: "Apartment 9D, Newhouse Court, 1 Acacia Avenue". Outside the number of flats is discreetly shown or not revealed. Where flats are lettered, this can also be indicated by appending the letter to the building number: "Flat D, 1 Acacia Avenue" may also be "1D Acacia Avenue" (generally only one of these formats will be officially used). • In some parts of Scotland, particularly Aberdeen and Dundee, flats in tenement blocks may be numbered as follows; "Flat 3/L, 1 Acacia Avenue". In this numbering system 3 refers to the floor (with G or 0 being used for the ground floor) and L or R indicating whether the flat is on the left or right from the entrance of the block.
Marking of numbers In the UK street numbering and street signposts vary across local authorities. Numbering plates (or similar) are overwhelmingly at the discretion of house owners. In the UK
fanlights in front doors were introduced in the 1720s in which the house number may be engraved. Contemporary architecture and modern house building techniques see alternatively acrylic, aluminium, or glass, ceramic, brass, slate, or stone used. ==Southern Europe==