Overcrowding or crowding is the condition where more people are located within a given space than is considered tolerable from a safety and health perspective which will depend on current environment and local cultural norms. Overcrowding may arise temporarily or regularly, in the home, public spaces or on public transport. The former is of particular concern since it is an individual's place of shelter.

Effects on quality of life due to crowding may be due to increased physical contact, lack of sleep, lack of privacy and poor hygiene practices.[1] While population density is an objective measure of number of people living per unit area, overcrowding refers to people's psychological response to density. But, definitions of crowding used in statistical reporting and for administrative purposes are based on density measures and do not usually incorporate people’s perceptions of crowding.

Measures of overcrowding

United States

The American Housing Survey is conducted by the United States Department of Housing and Urban Development (HUD) every two years.[2] A 2007 literature review conducted for HUD's Office of Policy Development and Research found that the most commonly used measures of overcrowding are persons-per-room or persons-per-bedroom.[3] The United States uses persons per room, and considers a household crowded if there is more than one person per room, and severely crowded if more than 1.5 persons share a room.[4]

World Health Organization

The World Health Organization is concerned with overcrowding of sleeping accommodation primarily as a risk for the spread of tuberculosis and has attempted to develop measurement indicators.[5]

United Kingdom

The Housing Act 1985 states:

"The room standard is contravened when the number of persons sleeping in a dwelling and the number of rooms available as sleeping accommodation is such that two persons of opposite sex who are not living together as husband and wife must sleep in the same room. For this purpose, children under the age of ten shall be left out of account, and a room is available as sleeping accommodation if it is of a type normally used in the locality either as a bedroom or as a living room."[6]

The Housing Act describes how many persons are permitted per room, as well as amount of floor space per room as outlined in the table below. Children under 1 year are not counted, and children between 1 and 10 years are counted as half a unit.

Area (in sq. ft) No. of persons
110 or more 2 persons
90 to 110 1.5 persons
70 to 90 1 person
50 to 70 0.5 persons

European Union

Eurostat uses a stricter definition of overcrowding, known as 'the Bedroom Standard'. An overcrowded household is defined as one which has fewer rooms than the sum of:[7]