In 2021, the infant mortality rate in the United Kingdom was four deaths one year per 1,000 live births, one of the lowest infant mortality rate in this period. Infant mortality has fallen considerably since 1900, when there were 150 infant deaths per 1,000 live births.

The child mortality rate in the United Kingdom, for children under the age of five, was 329 deaths per thousand births in 1800. This means that approximately one in every three children born in 1800 did not make it to their fifth birthday. Over the course of the next 220 years, this number has dropped drastically, particularly in the first half of the twentieth century, and the rate has dropped to its lowest point ever in 2020 where it is just four deaths per thousand births.

There were 2,784 infant deaths in the United Kingdom in 2021, compared with 2,620 in the previous year. The number of infant deaths in 2020 was the fewest in the provided time period, especially compared with 1900 when there were 163,470 infant deaths.

In the United Kingdom, the crude birth rate in 1800 was 37 live births per thousand people, meaning that 3.7 percent of the population had been born in that year. From 1800 until 1830, the crude birth rate jumped between 35 and 45, before plateauing between 35 and 37 until the 1880s. From 1880 until the Second World War, the crude birth rate dropped to just under fifteen births per one thousand people, with the only increase coming directly after World War One. After WWII, the United Kingdom experienced a baby boom, as many soldiers returned home and the economy recovered, however this boom stopped in the late 1960s and the crude birth rate went into decline again. From the late 1970s until today, the crude birth rate has remained between eleven and fourteen, and is expected to be 11.5 in 2020.

In 2021 the live birth rate of the United Kingdom fell to 10.4 births per 1,000 population, the lowest it had been during this time period. The UK's birth rate has been declining steadily since 2010 when the birth rate was 12.9 births per 1,000 population. After 1938, the year with the highest birth rate in the UK was 1947, when the crude birth rate was 21.2 births per 1,000 population. Under two children per mother in 2021 The most recent crude live birth rate for this statistic is based on the 694,685 births, that occurred in 2021 as well as the mid-year population estimate of 67 million for the United Kingdom. It has a close relation to the fertility rate which estimates the average number of children women are expected to have in their lifetime, which was 1.53 in this reporting year. Among the constituent countries of the UK, Northern Ireland had the highest birth rate at 11.6, followed by England at 10.5, Wales at 9.3, and Scotland at 8.7. International comparisons The UK is not alone in seeing its birth and fertility rates decline dramatically in recent decades. Across the globe, fertility rates have fallen noticeably since the 1960s, with the fertility rate for Asia, Europe, and the Americas being below two in 2021. As of this year, the global fertility rate was 2.31, and was by far the highest in Africa, which had a fertility rate of 4.12, although this too has fallen from a high of 6.72 in the late 1960s. A reduction in infant mortality, as well as better access to contraception, are factors that have typically influenced declining fertility rates recently.

The fertility rate of a country is the average number of children that women from that country would have throughout their reproductive years. In the United Kingdom in 1800, the average woman of childbearing age would have five children over the course of their lifetime. Over the next 35 years the fertility rate was quite sporadic, rising to over 5.5 in the 1810s and 1820s, then dropping to 4.9 by 1835. This was during and after the Napoleonic Wars and the War of 1812 with the US, which was a time of increased industrialization, economic depression and high unemployment after the war. As things became more stable, and the 'Pax Britannica' (a period of relative, international peace and economic prosperity for the British Empire) came into full effect, the fertility rate plateaued until 1880, before dropping gradually until the First World War. The fertility rate then jumped from 2.6 to 3.1 children per woman between 1915 and 1920, as many men returned from the war. It then resumed it's previous trajectory in the interwar years, before increasing yet again after the war (albeit, for a much longer time than after WWI), in what is known as the 'Baby Boom'. Like the US, the Baby Boom lasted until around 1980, where it then fell to 1.7 children per woman, and it has remained around this number (between 1.66 and 1.87) since then.

There were almost 695,000 live births recorded in the United Kingdom in 2021, compared with almost 682,000 in the previous year. Between 1887 and 2021, the year with the highest number of live births was 1920, when there were approximately 1.13 million births, while the year with the fewest births was 1977, when there were approximately 657,000 births. Birth rate falls to a historic low in 2020 At 10.2 births per 1,000 people, the birth rate of the United Kingdom in 2020 was at a historic low. After witnessing a twenty-first century high of 12.9 in 2010, the birth rate gradually declined before a sharp decrease was recorded between 2012 and 2013. Although there was a slight uptick in the birth rate in 2021, when there were 10.4 births per 1,000 people, the total fertility rate reached a low of 1.53 births per woman in the same year. As well as falling birth and fertility rates, the average age of mothers has been increasing. In 1991, the average age of mothers at childbirth was 27.7 years, compared with 30.9 years in 2021. UK population reaches 68 million In 2023, the overall population of the United Kingdom reached almost 68.3 million people. Of the four countries that comprise the UK, England has by far the highest population, at 57.7 million, compared with almost 5.5 million in Scotland, 3.2 million in Wales, and 1.9 million in Northern Ireland. These countries are far less densely populated than England, especially when compared to London, which had approximately 5,630 people per square kilometer, compared with just 70 in Scotland. After London, North West England was the second-most densely populated area of the UK, which includes the large metropolitan areas of the cities of Manchester, and Liverpool

Life expectancy in the United Kingdom was below 39 years in the year 1765, and over the course of the next two and a half centuries, it is expected to have increased by more than double, to 81.1 by the year 2020. Although life expectancy has generally increased throughout the UK's history, there were several times where the rate deviated from its previous trajectory. These changes were the result of smallpox epidemics in the late eighteenth and early nineteenth centuries, new sanitary and medical advancements throughout time (such as compulsory vaccination), and the First world War and Spanish Flu epidemic in the 1910s.

A global phenomenon, known as the demographic transition, has seen life expectancy from birth increase rapidly over the past two centuries. In pre-industrial societies, the average life expectancy was around 24 years, and it is believed that this was the case throughout most of history, and in all regions. The demographic transition then began in the industrial societies of Europe, North America, and the West Pacific around the turn of the 19th century, and life expectancy rose accordingly. Latin America was the next region to follow, before Africa and most Asian populations saw their life expectancy rise throughout the 20th century.

In 2022 life expectancy for both males and females at birth fell when compared to 2021. Male life expectancy fell from 78.71 years to 78.57 years, and from 82.68 years to 82.57 years for women. Throughout most of this period, there is a steady rise in life expectancy for both males and females, with improvements in life expectancy beginning to slow in the 2010s and then starting to decline in the 2020s. Life expectancy since the 18th Century Although there has been a recent dip in life expectancy in the UK, long-term improvements to life expectancy stretch back several centuries. In 1765, life expectancy was below 39 years, and only surpassed 40 years in the 1810s, 50 years by the 1910s, 60 years by the 1930s and 70 by the 1960s. While life expectancy has broadly improved since the 1700s, this trajectory was interrupted at various points due to wars and diseases. In the early 1920s, for example, life expectancy suffered a noticeable setback in the aftermath of the First World War and Spanish Flu Epidemic. Impact of COVID-19 While improvements to UK life expectancy stalled during the 2010s, it wasn't until the 2020s that it began to decline. The impact of COVID-19 was one of the primary factors in this respect, with 2020 seeing the most deaths in the UK since 1918. The first wave of the pandemic in Spring of that year was a particularly deadly time, with weekly death figures far higher than usual. A second wave that winter saw a peak of almost 5,700 excess deaths a week in late January 2021, with excess deaths remaining elevated for several years afterward.

At the beginning of the 1840s, life expectancy from birth in Ireland was just over 38 years. However, this figure would see a dramatic decline with the beginning of the Great Famine in 1845, and dropped below 21 years in the second half of the decade (in 1849 alone, life expectancy fell to just 14 years). The famine came as a result of a Europe-wide potato blight, which had a disproportionally devastating impact on the Irish population due to the dependency on potatoes (particularly in the south and east), and the prevalence of a single variety of potato on the island that allowed the blight to spread faster than in other areas of Europe. Additionally, authorities forcefully redirected much of the country's surplus grain to the British mainland, which exacerbated the situation. Within five years, mass starvation would contribute to the deaths of over one million people on the island, while a further one million would emigrate; this also created a legacy of emigration from Ireland, which saw the population continue to fall until the mid-1900s, and the total population of the island is still well below its pre-famine level of 8.5 million people.

Following the end of the Great Famine, life expectancy would begin to gradually increase in Ireland, as post-famine reforms would see improvements in the living standards of the country’s peasantry, most notably the Land Wars, a largely successful series of strikes, boycotts and protests aimed at reform of the country's agricultural land distribution, which began in the 1870s and lasted into the 20th century. As these reforms were implemented, life expectancy in Ireland would rise to more than fifty years by the turn of the century. While this rise would slow somewhat in the 1910s, due to the large number of Irish soldiers who fought in the First World War and the Spanish Flu pandemic, as well as the period of civil unrest leading up to the island's partition in 1921, life expectancy in Ireland would rise greatly in the 20th century. In the second half of the 20th century, Ireland's healthcare system and living standards developed similarly to the rest of Western Europe, and today, it is often ranks among the top countries globally in terms of human development, GDP and quality of healthcare. With these developments, the increase in life expectancy from birth in Ireland was relatively constant in the first century of independence, and in 2020 is estimated to be 82 years.

In 2024, the population of the United Kingdom reached 69.3 million, compared with 68.5 million in 2023. The UK population has more than doubled since 1871 when just under 31.5 million lived in the UK and has grown by around 10.4 million since the start of the twenty-first century. For most of the twentieth century, the UK population steadily increased, with two noticeable drops in population occurring during World War One (1914-1918) and in World War Two (1939-1945). Demographic trends in postwar Britain After World War Two, Britain and many other countries in the Western world experienced a 'baby boom,' with a postwar peak of 1.02 million live births in 1947. Although the number of births fell between 1948 and 1955, they increased again between the mid-1950s and mid-1960s, with more than one million people born in 1964. Since 1964, however, the UK birth rate has fallen from 18.8 births per 1,000 people to a low of just 10.2 in 2020. As a result, the UK population has gotten significantly older, with the country's median age increasing from 37.9 years in 2001 to 40.7 years in 2022. What are the most populated areas of the UK? The vast majority of people in the UK live in England, which had a population of 58.6 million people in 2024. By comparison, Scotland, Wales, and Northern Ireland had populations of 5.5 million, 3.2 million, and 1.9 million, respectively. Within England, South East England had the largest population, at over 9.6 million, followed by the UK's vast capital city of London, at almost 9.1 million. London is far larger than any other UK city in terms of urban agglomeration, with just four other cities; Manchester, Birmingham, Leeds, and Glasgow, boasting populations that exceed one million people.

The World Health Organization (WHO) estimates that there were millions of smallpox cases every year until the 1970s, when the WHO's eradication program then successfully eliminated the disease in nature. Some academic estimates place smallpox's death toll at 300 million in the twentieth century, and 500 million in its final hundred years of existence. The development of the smallpox vaccination, which was the first successfully developed vaccine (the word vaccination comes from the Latin word for cow;"vacca", as cowpox was used to develop the smallpox vaccine), greatly contributed to the significant decline in infant and child mortality across the globe, and the boom in population growth during the twentieth century. Reported cases In spite of these large numbers, the figures for reported cases was only a tiny fraction of this; for example, the WHO estimates that there were fifty million cases in 1950, however less than one percent of these cases were recorded. In spite of this, the data is still useful for showing how smallpox developed and spread throughout the world; we know that the majority of these cases were recorded in the Indian sub-continent, and that epidemics across Asia drove the number of recorded cases up in the middle of the century. The final naturally-occurring cases were observed in 1977, while the two cases in 1978 were due to a lab accident in England, which resulted in one fatality.

The statistic depicts the median age of the population in the United Kingdom from 1950 to 2100*. The median age of a population is an index that divides the population into two equal groups: half of the population is older than the median age and the other half younger. In 2020, the median age of United Kingdom's population was 39.2 years. Population of the United Kingdom The United Kingdom (UK) includes Great Britain (England, Scotland and Wales) and Northern Ireland, and is a state located off the coast of continental Europe. The United Kingdom is a constitutional monarchy, which means the Queen acts as representative head of state, while laws and constitutional issues are discussed and passed by a parliament. The total UK population figures have been steadily increasing, albeit only slightly, over the last decade; in 2011, the population growth rate was lower than in the previous year for the first time in eight years. Like many other countries, the UK and its economy were severely affected by the economic crisis in 2009. Since then, the unemployment rate has doubled and is only recovering slowly. UK inhabitants tend to move to the cities to find work and better living conditions; urbanization in the United Kingdom has been on the rise. At the same time, population density in the United Kingdom has been increasing due to several factors, for example, the rising number of inhabitants and their life expectancy at birth, an increasing fertility rate, and a very low number of emigrants. In fact, the United Kingdom is now among the 20 countries with the highest life expectancy at birth worldwide. As can be seen above, the median age of UK residents has also been increasing significantly since the seventies; another indicator for a well-working economy and society.

Life expectancy in India was 25.4 in the year 1800, and over the course of the next 220 years, it has increased to almost 70. Between 1800 and 1920, life expectancy in India remained in the mid to low twenties, with the largest declines coming in the 1870s and 1910s; this was because of the Great Famine of 1876-1878, and the Spanish Flu Pandemic of 1918-1919, both of which were responsible for the deaths of up to six and seventeen million Indians respectively; as well as the presence of other endemic diseases in the region, such as smallpox. From 1920 onwards, India's life expectancy has consistently increased, but it is still below the global average.