Figures for the population of Europe vary according to the particular definition of Europe's boundaries. In 2018, Europe had a total population of over 745 million people. Around 448 million of them lived in the European Union and around 110 million in European Russia; Russia is the most populous country in Europe.

Europe's population growth is low, and its median age high. Most of Europe is in a mode of sub-replacement fertility, which means that each new(-born) generation is less populous than the one before. Nonetheless, most West European countries still have growing populations, mainly due to immigration within Europe and from outside Europe and some due to increases in life expectancy and population momentum. Some current and past factors in European demography have included emigration, ethnic relations, economic immigration, a declining birth rate and an ageing population.

Approximately 5,000–130,000 people lived in Europe during the Last Glacial Maximum about 20,000 years ago.

According to Volker Heyd, an archaeologist at the University of Helsinki, up to 7 million people lived in Neolithic Europe in 3000 BC.

According to archaeologist Johannes Müller, the European population was about 1 million around 6500 BC, but increased to 8 million in 2000 BC.

The following table shows estimates of historical population sizes of Europe (including Central Asia, listed under "former USSR") based on Maddison (2007), in millions, with an estimated percentage of world population:

330,000,000 people lived in Europe in 1916. In 1950 there were 549,000,000. The population of Europe in 2015 was estimated to be 741 million according to the United Nations, which was slightly less than 11% of the world population. The precise figure depends on the exact definition of the geographic extent of Europe. The population of the European Union (EU) was 509 million as of 2015. Non-EU countries situated in Europe in their entirety account for another 90 million. Five transcontinental countries have a total of 247 million people, of which about half reside in Europe proper.

As it stands now, around 10% of the world's people live in Europe. If demographic trends keep their pace, its share may fall to around 7% in 2050, but still amounting to 716 million people in absolute numbers, according to the United Nations estimate. (The decline in the percentage is partly due to high fertility rates in Africa and South America.) The sub-replacement fertility and high life expectancy in most European states mean a declining and aging population. High immigration and emigration levels within and from outside the continent are taking place and quickly changing countries, specifically in Western Europe, from a single ethnic group to a multicultural society. These trends can change societies' economies as well as their political and social institutions. ^{[how?][citation needed]}