The household is the centre of family life, an environment of cohabitation and a unit of consumption and economic protection, as well as a space for socialisation and social reproduction. The size and composition of households determine all these functions and influence housing needs, demand for goods and services, government spending, and savings. In turn, the size and structure of households are flexible elements, shaped by family and demographic changes, economic conditions, and various cultural aspects related to the family. 

This report analyses the transformation of households in Spain and Portugal from 1991 to 2022, using data from the Economically Active Population Survey (EAPS). The study combines the classic perspective of households with an individual perspective based on the structures of cohabitation by age and sex. The analysis draws on the total population, without distinguishing according to origin.
 

In the last three decades – specifically, between 1991 and 2022 – the average household size in Spain has fallen from 3.3 to 2.4 people, while in Portugal it has dropped from 3.1 to 2.5 people. 



This decrease has helped to reduce, and even eliminate, the differences with other countries, such as the United States (2.5 in 2022) and the United Kingdom (2.4 in 2022). This trend is the result of a notable increase in single-person and two-person households, and a sharp decrease in four-person and five-person households. 

With respect to three-person households, these have remained relatively stable.



During this period, the total population has increased by 21.9% in Spain and by 4.4% in Portugal. As a result of these trends, the total number of households has increased in both countries to reach 19.75 million in Spain and 4.11 million in Portugal, representing an increase of 67.7% and 25.9%, respectively. The factor that has contributed most to this increase has been the reduction in average household size, responsible for 68% of the increase in the number of households in Spain and 85% of the increase in Portugal. Population growth has not been the same in both countries due to the differing impact of international immigration, which is much more significant in Spain than in Portugal.

The transformation of the size and composition of households can be observed from an individual perspective through an analysis of the structures of cohabitation by age and sex. These structures reflect people’s family context according to their age, sex, and other variables that one may wish to analyse. The following graph shows the relative distribution of cohabitation structures by age and sex in Spain and Portugal during the years 1991 and 2022. In total, 13 categories are identified, differentiated according to whether people live alone or accompanied.



Among people who live in the company of others, the typology distinguishes between non-family households (“With non-relatives”) and family structures, which group together the majority of the population. Within the family structures, 11 types are distinguished according to the relative position of the ego with respect to their relatives and the presence or absence of an extended family. The structures of cohabitation by age and sex reflect, with variations, the usual stages of the life cycle: cohabitation with parents during childhood and adolescence; beginning of life as a couple and with children in adulthood, and living together as a couple or alone at advanced ages. 

The structures of cohabitation are similar between men and women in childhood and youth. Gender differences emerge when they begin to live together as a couple and with the arrival of children, occurring earlier in women, and with the impact that a breakup has on child custody, as it is more common for women to live with the children after separation. In older ages, these differences are amplified: there are more women than men who live alone. This is partly due to the fact that women are widowed earlier than men because of their longer life expectancy and because their partners tend to be older. It is also due to the fact that women are less likely to live with a new partner after a breakup or the death of a spouse. 

The changes observed over time show an increase in structures with only one parent during childhood, a prolonged period of cohabitation with parents, a delay in the start of life as a couple or with children, and, at advanced ages, a decrease in cohabitation with children and extended family, along with an increase in the number of people living alone.
 

The following graph shows, for a standard life of eighty years, in both Spain and Portugal, the average number of years that a man and a woman would live in each of the 13 cohabitation structures in the years 1991 and 2022. The years lived indicator is a summary measure of the weight of each structure in each country and year. The three most common forms of cohabitation are: a) with both parents; b) only with partner, and c) with partner and children. Together, they represent more than forty years on average.



Living together in non-family homes is residual in both countries and in both periods. Years lived in nuclear structures (with no relatives beyond the partner and children) predominate over extended family structures. Categories such as “Alone”, “With only one parent” or “With children” accumulate between 2 and 8 years on average, depending on country, year, and sex. 

The changes over time show an increase in the number of years that people live alone, a figure that in Spain rises from 2.6 years in 1991 to 7.5 years in 2022. An increase is also observed among Spanish women (from 4.9 to 7.5 years), Spanish men (from 2.9 to 4.9 years) and Portuguese women (from 5.4 to 6.6 years). Likewise, the number of years lived with a single parent increases. In both countries, a reduction in the number of years in which people live with their partner and children is detected. All forms of cohabitation in an extended family – including living with other relatives – decrease. On the other hand, the number of years in which people live only with their partner, as well as those of cohabitation with both parents, in this case due to the delay in young people leaving home, increases. The impact of the reduction in household size is reflected in the increase in the average number of years spent living alone, in the decrease in the number of years lived with both parents, in the reduction in the time shared with partner and children, and in the decrease in the number of years spent in any type of extended family.
 

In the last three decades, both Spain and Portugal have undergone a profound transformation in terms of household size and composition. Between 1991 and 2022, the average household size decreased from 3.3 to 2.4 people in Spain, and from 3.1 to 2.5 people in Portugal. This decrease, driven mainly by the increase in single-person and two-person households, has been the main factor behind the growth of the total number of households.
 
From an individual perspective, a modification in the structures of cohabitation by age and sex is observed. The number of years during which people live alone is increasing – especially at advanced ages and among women – and the time spent living in the parental household is increasing due to the delay in young people leaving home. The number of years lived with partner and children decrease, as well as all forms of life in the extended family. In turn, single-parent structures during childhood, and cohabitation with a partner and without children increase. 

In terms of countries, no significant differences are observed between Spain and Portugal. Both share the same system of residential structures: young people leaving home at a late stage, predominance of the nuclear family during the central life stages, and an old age characterised by living with a partner or alone. 

Moreover, given the growing impact of immigration in both countries, especially in Spain, future research should address the differences between native and immigrant populations. The residential strategies of the immigrant population may differ from those of the native population, as well as being heterogeneous depending on origin. It is also probable that the unequal weight of immigration in each country may explain the minor differences observed between the two countries. 

These changes have relevant implications for public policies. The increase in single-person households and less intergenerational cohabitation increase demand for housing, social services, and economic support, especially in old age. The reduced presence of extended family structures reduces informal care networks, which requires greater State intervention in the provision of care services. In addition, the delay in young people leaving home poses challenges in access to housing and employment. These changes also affect consumption patterns, public spending, and socialisation dynamics, revealing the need to adapt family, housing and social protection policies to a society that presents increasingly diverse and fragmented cohabitation structures.