UK Population by Age Group: 2021 Census Breakdown
The 2021 Census counted 56.5 million people in England and Wales — the largest population ever recorded. This guide breaks down the age structure, explains what changed since 2011, and shows you how to use age data for planning, policy, and research.
England and Wales: The Headline Numbers
The 2021 Census recorded a usually resident population of 56,489,800 in England and Wales — an increase of 3.5 million (6.3%) from 53.0 million in 2011. This was the largest decade-on-decade increase since records began in 1801, driven primarily by natural growth (more births than deaths) and net international migration.
The population is also older than ever. The median age rose from 39 in 2011 to 40 in 2021. For the first time, there were more people aged 65 and over (10.4 million) than children under 15 (10.3 million).
| Age Group | Population (2021) | % of Total | Change from 2011 |
|---|---|---|---|
| 0–4 | 3,219,400 | 5.7% | -6.2% |
| 5–14 | 7,122,200 | 12.6% | +7.7% |
| 15–24 | 6,693,700 | 11.8% | -5.6% |
| 25–34 | 7,752,400 | 13.7% | +3.0% |
| 35–49 | 11,597,600 | 20.5% | -2.4% |
| 50–64 | 10,695,600 | 18.9% | +10.3% |
| 65–74 | 5,636,500 | 10.0% | +17.2% |
| 75–84 | 3,291,700 | 5.8% | +13.3% |
| 85+ | 1,480,700 | 2.6% | +14.3% |
The ageing shift: Between 2011 and 2021, every age group above 50 grew faster than the population as a whole. The 65–74 group expanded by 17.2%, driven by the large 1950s birth cohort ageing into retirement. Meanwhile, the 0–4 group shrank by 6.2%, reflecting falling birth rates since 2012.
Regional Age Profiles
Age structure varies dramatically across England and Wales. London has the youngest population profile of any region, with a median age of 35, driven by working-age international migration. The South West has the oldest, with a median age of 44, reflecting retirement migration to coastal and rural areas.
Youngest Regions (by median age)
- London — median age 35. Over 70% of the population is of working age (16–64). Tower Hamlets has the youngest local authority median age at 30.
- West Midlands — median age 39. Birmingham, the UK's second city, has a significant under-25 population driven by its large university sector and ethnically diverse communities.
- East Midlands — median age 41. Nottingham city brings the regional average down with its large student population.
Oldest Regions (by median age)
- South West — median age 44. Dorset Council has the highest median age of any English local authority at 51. Devon, Cornwall, and Somerset all have median ages above 45.
- Wales — median age 42. Conwy and Powys have significant retirement populations, while Cardiff (median 33) brings the national average down.
- North East — median age 42. Although urban centres like Newcastle are relatively young, the former industrial towns of County Durham and Northumberland have ageing populations.
Explore age data by local authority. See population breakdowns for any area in England and Wales.
Open Data ExplorerHow Age Data is Collected and Published
The 2021 Census asked every resident for their date of birth. ONS publishes age data in two main forms:
Single Year of Age
Table TS007 provides population counts for every single year of age (0 through 100+) at national, regional, and local authority level. This is the most granular age data available and is essential for actuarial work, education planning, and detailed demographic modelling.
Five-Year Age Bands
For most analytical purposes, five-year bands (0–4, 5–9, 10–14, etc.) are more practical. These are available at every geographic level down to Output Area, though OA-level data is rounded to protect confidentiality.
Age by Other Variables
The real power of census age data comes from cross-tabulations — age by ethnic group, age by economic activity, age by housing tenure, age by health status. These are published as separate table series (e.g., RM031 for age by ethnic group). Cross-tabulations are generally available at local authority level and above; some are available at MSOA level.
The Dependency Ratio
One of the most important metrics derived from age data is the dependency ratio — the number of people outside working age (under 16 or 65+) relative to the working-age population (16–64). It is a crude but powerful indicator of the economic burden on a local area's workforce.
For England and Wales overall:
- Total dependency ratio (2021): 57.5 per 100 working-age people
- Child dependency ratio: 28.2 per 100
- Old-age dependency ratio: 29.3 per 100
This means that for every 100 working-age adults, there are approximately 58 people who are either children or retirement-age. The old-age ratio exceeded the child ratio for the first time in the 2021 Census — a significant structural shift.
Where Dependency Ratios Are Highest
Coastal retirement areas have the highest old-age dependency ratios:
- North Norfolk: 53.1 per 100 (old-age)
- East Devon: 49.8 per 100
- Rother (East Sussex): 48.2 per 100
University cities often have low old-age dependency but unusual age pyramids due to the concentration of 18–24 year olds.
Policy implications: Areas with high old-age dependency ratios face pressure on adult social care, NHS community services, and public transport. Areas with high child dependency ratios need school places, children's services, and family housing. The census provides the baseline data for resource allocation formulae used by central government.
Changes Since 2011: What Drove the Shift?
Falling Birth Rates
The total fertility rate in England and Wales peaked at 1.94 in 2012 and fell to 1.61 by 2021 (ONS mid-year estimates). This explains the 6.2% decline in the 0–4 age group. The drop was steepest among women aged 20–24, partially offset by rising fertility rates among women in their 30s.
The Baby Boom Echo
The large cohorts born in the 1950s and early 1960s — the original baby boomers — moved through their 60s during the 2011–2021 decade. This explains the 17.2% increase in the 65–74 group. As these cohorts age further, the 75–84 and 85+ groups will swell significantly by the 2031 Census.
International Migration
Net migration added approximately 2.2 million people to the population between 2011 and 2021. Migrants disproportionately arrive in the 20–39 age range, which is why London's working-age population grew so substantially despite relatively low birth rates. Areas with high international migration — London, the South East, the East — have younger population profiles than areas where migration is lower.
COVID-19 Impact
The census was conducted during the third national lockdown. Excess deaths (primarily among older people) and reduced international in-migration during 2020–2021 may have slightly dampened the ageing trend compared to what pre-pandemic projections expected. ONS published quality notes on COVID-19's impact on census counts.
Practical Applications of Age Data
Education Planning
Local authorities use age data to forecast school place demand. The 5–9 and 10–14 age groups determine primary and secondary school pressures respectively. Areas where the 0–4 cohort is shrinking may need to consolidate primary schools; areas where it is growing need new provision.
Healthcare Commissioning
Integrated Care Boards (ICBs) use age profiles to plan services. An area with a rapidly growing 85+ population needs dementia care, falls prevention, end-of-life services, and domiciliary care capacity. An area with a young population needs maternity services, mental health support for young adults, and sexual health provision.
Housing Development
Age data informs housing mix decisions. A local authority with a growing 25–34 population needs starter homes and rental stock. One with a growing 65+ population needs accessible housing, bungalows, and supported living. Census age data feeds into Strategic Housing Market Assessments (SHMAs), which are required evidence for local plans.
Pension and Retirement Planning
The growing 50–64 cohort represents the next wave of retirees. Financial services firms use census age data (combined with employment and qualification data) to estimate pension demand, retirement savings gaps, and the geographic distribution of retirees with different income profiles.
Frequently Asked Questions
What is the average age in the UK?
The median age in England and Wales was 40 in 2021, up from 39 in 2011. The mean age was slightly higher at 40.7 years. Scotland's median age in 2022 was 42, and Northern Ireland's was 38.
Which age group is the largest in the UK?
The 35–49 working-age group was the largest in 2021 at 11.6 million (20.5% of the population). However, the fastest-growing groups were 65–74 (+17.2%) and 85+ (+14.3%), reflecting the ageing population.
How many over-65s are there in England and Wales?
The 2021 Census counted 10.4 million people aged 65 and over, representing 18.4% of the population — up from 16.3% in 2011. This exceeded the number of children under 15 (10.3 million) for the first time.
Where can I download age data by local authority?
ONS publishes Census 2021 age data via Nomis (nomis.co.uk) and the ONS census data downloads page. Table TS007 provides single year of age at all geographic levels. CensusWise also provides pre-processed age breakdowns in the Data Explorer.
Does the census include Scotland's age data?
No — the ONS 2021 Census covers England and Wales only. Scotland conducted its census in 2022, managed by National Records of Scotland, with results published from 2023. Scotland's population was 5.44 million, with a median age of 42.
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