In 2019, the population of Spain officially reached 47 million people, as recorded by the Padrón municipal (Spain’s Municipal Register). Spain’s population density, at 91/km2 (235/sq mi), is lower than that of most Western European countries and its distribution across the country is very unequal. With the exception of the region surrounding the capital, Madrid, the most populated areas lie around the coast. The population of Spain has risen 2 1/2 times since 1900, when it stood at 18.6 million, principally due to the spectacular demographic boom in the 1960s and early 1970s.

In 2017, the average total fertility rate (TFR) across Spain was 1.33 children born per woman, one of the lowest in the world, below the replacement rate of 2.1, it remains considerably below the high of 5.11 children born per woman in 1865. Spain subsequently has one of the oldest populations in the world, with the average age of 43.1 years.

Native Spaniards make up 88% of the total population of Spain. After the birth rate plunged in the 1980s and Spain’s population growth rate dropped, the population again trended upward initially upon the return of many Spaniards who had emigrated to other European countries during the 1970s, and more recently, fuelled by large numbers of immigrants who make up 12% of the population. The immigrants originate mainly in Latin America (39%), North Africa (16%), Eastern Europe (15%), and Sub-Saharan Africa (4%).

In 2008, Spain granted citizenship to 84,170 persons, mostly to people from Ecuador, Colombia and Morocco. Many foreign residents in Spain also come from other Western and Central European countries. These are mostly British, French, German, Dutch, and Norwegian. They reside primarily on the Mediterranean coast and the Balearic islands, where many are retired or remote workers.