There were over 4.7 million people aged between 30 and 34 in the United Kingdom in 2023, making it the most populous age group in that year. Those aged between 35 and 39 years comprised the next most numerous age group in 2023, at over 4.64 million people. Millennials overtake Boomers as biggest generation Post-war demographic trends, particularly the 'baby boom' phenomenon, have significantly influenced the current age distribution in the UK. The postwar peak of live births in 1947 resulted in the dominance of the Baby Boomer generation for several decades, until 2020 when Millennials became the largest generational cohort, surpassing the Boomers for the first time. The following year, the UK Boomer population was then overtaken by Generation X, the generation born between Boomers and Millennials. Generation Z, however, remains smaller than the three generations that preceded it, at 12.9 million individuals in 2022. Aging UK population poses challenges The median age of the UK population is projected to reach 44.5 years by 2050, compared to 34.9 years in 1950. This aging trend is indicative of broader global demographic shifts, with the median age of people worldwide forecasted to increase from 23.6 years in 1950 to 41.9 years by 2100. How countries like the UK manage their aging populations will be one of the key challenges of the next few decades. It is likely the UK's struggling National Health Service (NHS) will come under even more pressure in the coming years. There are also tough economic questions, in particular as more people enter retirement age and the UK's working population gets smaller in relation to it.

There were almost 4.8 million people aged between 30 and 34 in the United Kingdom in 2024, making it the most populous age group in that year. Those aged between 35 and 39 years comprised the next most numerous age group in this year, at over 4.78 million people. Millennials overtake Boomers as biggest generation Post-war demographic trends, particularly the 'baby boom' phenomenon, have significantly influenced the current age distribution in the UK. The postwar peak of live births in 1947 resulted in the dominance of the Baby Boomer generation for several decades, until 2020 when Millennials became the largest generational cohort, surpassing the Boomers for the first time. The following year, the UK Boomer population was then overtaken by Generation X, the generation born between Boomers and Millennials. Generation Z, however, remains smaller than the three generations that preceded it, at 12.9 million individuals in 2022. Aging UK population poses challenges The median age of the UK population is projected to reach 44.5 years by 2050, compared to 34.9 years in 1950. This aging trend is indicative of broader global demographic shifts, with the median age of people worldwide forecasted to increase from 23.6 years in 1950 to 41.9 years by 2100. How countries like the UK manage their aging populations will be one of the key challenges of the next few decades. It is likely the UK's struggling National Health Service (NHS) will come under even more pressure in the coming years. There are also tough economic questions, in particular as more people enter retirement age and the UK's working population gets smaller in relation to it.