The world’s population is expected to increase by 2.6 billion over the next 45 years, from 6.5 billion today to 9.1 billion in 2050. Almost all growth will take place in the less developed regions, where today’s population of 5.3 billion is expected to swell to 7.8 billion in 2050. By contrast, the population of the more developed regions will remain mostly unchanged, at 1.2 billion.

The Population Division of the Department of Economic and Social Affairs has prepared theofficial United Nations estimates and projections of the world’s population since 1951. The 2004 Revision of the World Population Prospects represents the nineteenth revision. The 2004 Revision is the first to incorporate the full results of the 2000 round of national population censuses. It also takes into account the results of recent specialized surveys carried out in developing countries. These surveys provide both population and other data to assess progress made in achieving the internationally agreed development goals, including the Millennium Development Goals. The comprehensive review of past demographic trends and future prospects presented in the 2004 Revision provides the relevant demographic trends for the assessment of these goals.


  1. By July 2005, the world will have 6.5 billion inhabitants, 380 million more than in 2000 or a gain of 76 million annually. Despite the declining fertility levels projected over 2005-2050, world population is expected to reach 9.1 billion according to the medium variant and will still be adding 34 million persons annually by mid-century.

  2. Today, 95 per cent of all population growth is absorbed by the developing world and 5 percent by the developed world. By 2050, according to the medium variant, the population of the more developed countries as a whole would be declining slowly by about 1 million persons a year and that of the developing world would be adding 35 million annually, 22 million of whom would be absorbed by the least developed countries.

  3. Future population growth is highly dependent on the path that future fertility takes. In the medium variant, fertility is projected to decline from 2.6 children per woman today to slightly over 2 children per woman in 2050. If fertility was to remain about half a child above the levels projected in the medium variant, world population would reach 10.6 billion by 2050. A fertility path half a child below the medium variant would lead to a population of 7.6 billion by mid-century. That is, at the world level, continued population growth until 2050 is inevitable even if the decline of fertility accelerates.

  4. Because of its low and declining rate of growth, the population of developed countries as a whole is expected to remain virtually unchanged between 2005 and 2050, at about 1.2 billion. In contrast, the population of the 50 least developed countries is projected to more than double, passing from 0.8 billion in 2005 to 1.7 billion in 2050. Growth in the rest of the developing world is also projected to be robust, though less rapid, with its population rising from 4.5 billion to 6.1 billion between 2005 and 2050.

  5. Very rapid population growth is expected to prevail in a number of developing countries, the majority of which are least developed. Between 2005 and 2050, population is projected to at least triple in Afghanistan, Burkina Faso, Burundi, Chad, the Congo, the Democratic Republic of the Congo, Guinea-Bissau, Liberia, Mali, the Niger, Timor-Leste and Uganda.

  6. The population of 51 countries or areas, including Germany, Italy, Japan, the Baltic States and most of the successor countries of the former Soviet Union, is expected to be lower in 2050 than in 2005.

  7. During 2005-2050, nine countries are expected to account for half of the world’s projected population increase: India, Pakistan, Nigeria, the Democratic Republic of the Congo, Bangladesh, Uganda, the United States of America, Ethiopia and China, listed according to the size of their contribution to population growth during that period.

  8. In 2000-2005, fertility at the world level stood at 2.65 children per woman, about half that of 1950-1955 (5 children per woman). In the medium variant, global fertility is projected to decline further, to 2.05 children per woman by 2045-2050. Average world levels result from quite different trends by major development group. In developed countries as a whole, fertility is currently 1.56 children per woman and is projected to increase slowly to 1.84 children per woman in 2045-2050. In the least developed countries, fertility is 5 children per woman and is expected to drop by about half, to 2.57 children per woman by 2045-2050. In the rest of the developing world, fertility is already moderately low at 2.58 children per woman and is expected to decline further to 1.92 children per woman by mid-century, thus nearly converging to the fertility levels by then typical of the developed world. Realization of the fertility declines projected is contingent on access to family planning, especially in the least developed countries.

  9. In 2000-2005, fertility remains above 5 children per woman in 35 of the 148 developing countries, 30 of which are least developed countries, while the pace of decline in several countries of sub-Saharan Africa and South-central Asia has been slower than anticipated. Overall, the countries with high fertility account for 10 per cent of the world population. In contrast, fertility has reached below-replacement levels in 23 developing countries accounting for 25 per cent of the world population. This group includes China, where fertility during 2000-2005 is estimated at 1.7 children per woman.

  10. Fertility levels in the 44 developed countries, which account for 19 per cent of world population, are currently very low. All except Albania have fertility below replacement level and 15, mostly located in Southern and Eastern Europe, have reached levels of fertility unprecedented in human history (below 1.3 children per woman). Since 1990-1995, fertility decline has been the rule among most developed countries. The few increases recorded, such as those in Belgium, France, Germany, the Netherlands and the United States, have been small.

  11. Global life expectancy at birth, which is estimated to have risen from 47 years in 1950-1955 to 65 years in 2000-2005, is expected to keep on rising to reach 75 years in 2045-2050. In the more developed regions, the projected increase is from 76 years today to 82 years by midcentury. Among the least developed countries, where life expectancy today is 51 years, it is expected to be 67 years in 2045-2050. Because many of these countries are highly affected by the HIV/AIDS epidemic, the projected increase in life expectancy is dependent on the implementation of effective programmes to prevent and treat HIV infection. In the rest of the developing world, under similar conditions, life expectancy is projected to rise from 66 years today to 76 years by mid-century.

  12. Mortality in Eastern Europe has been increasing since the late 1980s. In 2000-2005 life expectancy in the region, at 67.9 years, was lower than it had been in 1960-1965 (68.6 years). The Russian Federation and Ukraine are particularly affected by rises in mortality resulting partly from the spread of HIV.

  13. Twenty-five years into the HIV/AIDS epidemic, the impact of the disease is evident in terms of increased morbidity and mortality and slower population growth. In Southern Africa, the region with the highest HIV/AIDS prevalence, life expectancy has fallen from 62 years in 1990-1995 to 48 years in 2000-2005, and is projected to decrease further to 43 years over the next decade before a slow recovery starts. As a consequence, population growth in the region is expected to stall between 2005 and 2020. In Botswana, Lesotho and Swaziland, the population is projected to decrease as deaths outnumber births. In most of the other developing countries affected by the epidemic, population growth will continue to be positive because their moderate or high fertility more than counterbalances the rise in mortality.

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  15. he primary consequence of fertility decline, especially if combined with increases in life expectancy, is population ageing, whereby the share of older persons in a population grows relative to that of younger persons. Globally, the number of persons aged 60 years or over is expected almost to triple, increasing from 672 million in 2005 to nearly 1.9 billion by 2050. Whereas 6 out of every 10 of those older persons live today in developing countries, 8 out of every 10 will do so by 2050. An even more marked increase is expected in the number of the oldest-old (persons aged 80 years or over): from 86 million in 2005 to 394 million in 2050. In developing countries, the rise will be from 42 million to 278 million, implying that by 2050 most oldest-old will live in the developing world.

  16. In developed countries, 20 per cent of today’s population is aged 60 years or over, and by 2050 that proportion is projected to be 32 per cent. The elderly population in developed countries has already surpassed the number of children (persons aged 0-14), and by 2050 there will be 2 elderly persons for every child. In the developing world, the proportion of the population aged 60 or over is expected to rise from 8 per cent in 2005 to close to 20 per cent by 2050.

  17. Increases in the median age, the age at which 50 per cent of the population is older and 50 per cent younger than that age, are indicative of population ageing. Today, just 11 developed countries have a median age above 40 years. By 2050, there will be 89 countries in that group, 45 in the developing world. Population ageing, which is becoming a pervasive reality in developed countries, is also inevitable in the developing world and will occur faster in developing countries.

  18. Countries where fertility remains high and has declined only moderately will experience the slowest population ageing. By 2050, about one in five countries is still projected to have a median age equal to or less than 30 years. The youngest populations will be found in least developed countries, 11 of which are projected to have median ages equal to or less than 23 years in 2050, including Afghanistan, Angola, Burundi, Chad, the Democratic Republic of the Congo, Equatorial Guinea, Guinea-Bissau, Liberia, Mali, the Niger and Uganda.

  19. During 2005-2050, the net number of international migrants to more developed regions is projected to be 98 million, or an average of 2.2 million annually. The same number will leave the less developed regions. For the developed world, such a level of net migration will largely offset the expected excess of deaths over births during 2005-2050, which amounts to a loss of 73 million people. For the developing world, the 98 million emigrants represent scarcely less than 4 per cent of expected population growth.

  20. In terms of annual averages for the period 2005-2050, the major net receivers of international migrants are projected to be the United States (1.1 million annually), Germany (202,000), Canada (200,000), the United Kingdom of Great Britain and Northern Ireland (130,000), Italy (120,000) and Australia (100,000). The major countries of net emigration are projected to be China (-327,000 annually), Mexico (-293,000), India (-241,000), the Philippines (-180,000), Indonesia (-164,000), Pakistan (-154,000) and Ukraine (-100,000).

  21. Over the period 2000-2005, 74 countries were net receivers of migrants. In 64 of these countries, the net migration projected reinforces population growth, and in 7 countries it reverses the trend of population decline (Austria, Croatia, Germany, Greece, Italy, Slovakia and Slovenia). In three countries, the migration slows down population decline but does not reverse it (the Czech Republic, Hungary and the Russian Federation).

See wall chart with all population data and projections

In addition to this wallchart, the full results and analysis of the 2004 Revision will be issued in a series of three volumes and a set of three CD-ROMs. A population database containing the results is available on the United Nations Population Division’s website at www.unpopulation.org. Enquiries and comments should be addressed to the Office of the Director, Population Division, Department of Economic and Social Affairs, United Nations, New York, NY 10017, USA; fax number: (212) 963-2147.