In 2022, the life expectancy at birth for women born in the UK was 82.57 years, compared with 78.57 years for men. By age 65 men had a life expectancy of 18.25 years, compared with 20.76 years for women.

In 2023, there were estimated to be 956,116 people who were aged 35 in the United Kingdom, the most of any age in this year. The two largest age groups during this year were 30-34, and 35 to 39, at 4.7 million and 4.64 million people respectively. There is also a noticeable spike of 693,679 people who were aged 76, which is due to the high number of births that followed in the aftermath of the Second World War. Over one million born in 1964 In post-war Britain, there have only been two years when the number of live births was over one million, in 1947 and in 1964. The number of births recorded in the years between these two years was consistently high as well, with 1955 having the fewest births in this period at 789,000. This meant that until relatively recently, Baby Boomers were the largest generational cohort in the UK. As of 2022, there were approximately 13.76 million Baby Boomers, compared with 14 million in Generation X, 14.48 million Millennials, and 12.9 million members of Gen Z. The youngest generation in the UK, Generation Alpha numbered approximately 7.5 million in the same year. Median age to hit 44.5 years by 2050 The population of the United Kingdom is aging at a substantial rate, with the median age of the population expected to reach 44.5 years by 2050. By comparison, in 1950 the average age in the United Kingdom stood at 34.9 years. This phenomenon is not unique to the United Kingdom, with median age of people worldwide increasing from 23.6 years in 1950 to a forecasted 41.9 years by 2100. As of 2022, the region with the oldest median age in the UK was South West England, at 43.9 years, compared with 35.9 in London, the region with the youngest median age.

As of 2023, there were approximately 13.57 million members of the Baby Boomer generation in the United Kingdom, ranging from the ages of 59 to 77. The most-common single year of age for Baby Boomers in this year was 59, at 915,735, while there were 521,896 who were 77, the least common year of age.

In 2023, there were approximately ***** million millennials in the United Kingdom, making it the largest generational cohort at that time. Millennials surpassed the Baby Boomer generation as the largest generation for the first time in 2019. The two youngest generations, Gen Z and Gen Alpha, numbered approximately **** million, and *** million respectively. Gen X are, as of the most recent year, the second-largest generation in the UK at ***** million people, with their parent's generation, the Silent Generation, numbering around *** million people in the same year. There were estimated to be ****** people who belonged to the Greatest Generation, the parents of the Baby Boomer generation, who lived through major events such as the Great Depression and World War Two. Post-War Baby Boom The baby boomer generation was the largest generation for much of this period due to the spike in births that happened after the Second World War. In 1947, for example, there were over *** million live births in the United Kingdom, compared with just ******* live births just thirty years later in 1977. Members of this generation are typically the parents of millennials, and were the driving force behind the countercultural movement of the 1960s, due to their large numbers relative to older generations at the time. The next generational cohort after Boomers are Generation X, born between 1965 and 1980. This generation had fewer members than the Boomer generation for most of its existence, and only became larger than it in 2021. Millennials and Gen Z As of 2022, the most common single year of age in the United Kingdom in 2020 was 34, with approximately ******* people this age. Furthermore, people aged between 30 and 34 were the most numerous age group in this year, at approximately 4.67 million people. As of 2022, people in this age group were Millennials, the large generation who came of age in the late 1990s and early 2000s. Many members of this generation entered the workforce following the 2008 financial crash, and suffered through high levels of unemployment during the early 2010s. The generation that followed Millennials, Generation Z, have also experienced tough socio-economic conditions recently, with key formative years dominated by the COVID-19 pandemic, climate change, and an increasingly unstable geopolitical situation.