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2021 Census

Population and household estimates, Wales: Census 2021

The Office for National Statistics (ONS) published the first results from the 2021 Census for Wales (Office for National Statistics) and England on 28 June. These first results include rounded population and household estimates for local authorities in Wales, by sex and five-year age groups.

The Welsh Government has also published a statistical bulletin summarising the key results for Wales. The data have also been made available on StatsWales.

Main points

Population change

  • On Census Day, 21 March 2021, the size of the usual resident population in Wales was estimated to be 3,107,500. This was the largest population ever recorded through a census in Wales.
  • The population of Wales has grown by 44,000 (1.4%) since the last census in 2011, when it was 3,063,456.
  • The rate of population growth in Wales between 2011 and 2021 (1.4%) was lower than the rate between 2001 and 2011, when the population grew by 5.5%.
  • The rate of population growth in Wales was considerably lower than in England, where the population grew by 6.6% (almost 3.5 million).
  • There were more deaths than births in Wales between 2011 and 2021. The population growth since 2011 is due to positive net migration into Wales (approximately 55,000 usual residents).

Local authority populations

  • The local authorities that had the highest rates of population increase since 2011 were in Newport (9.5%), Cardiff (4.7%), and Bridgend (4.5%).
  • Several local authorities had lower populations in 2021 than in 2011. The greatest rates of population decrease since 2011 were in Ceredigion (5.8%), Blaenau Gwent (4.2%) and Gwynedd (3.7%).

Population by age

  • There were more people than ever before in older age groups in Wales. The proportion of the population who were aged 65 years or older was 21.3% (up from 18.4% in 2011).
  • Wales had a larger percentage of the population aged 65 years or older than all English regions except South West England, where 22.3% of the population were in this age group.
  • The size of the population aged 90 years or older in Wales (29,700, 1.0%) has increased since 2011, when 25,200 (0.8%) were 90 years or older.

Population density

  • On average there were 150 residents per square kilometre in Wales in 2021, considerably lower than the population density in England (434 residents per square kilometre).
  • The most densely populated local authority in Wales was Cardiff (2,572 residents per square kilometre), while Powys was the least densely populated (26 residents per square kilometre).

Number of households

  • There were 1,347,100 households with at least one usual resident in Wales on Census Day. This is an increase of 44,400 (3.4%) since 2011, when there were 1,302,676 households.

The ONS has published an interactive scrolly-telling article about how the population has changed where you live (Office for National Statistics), which visualises the first results from the 2021 Census in Wales and England at a local level.

There is also a 2021 Census population map game (Office for National Statistics), which is an online game based on 2021 Census data, which challenges players to make their way across a map of Wales and England by correctly guessing facts about neighbouring local authorities.

ONS 2021 Census release plans

The ONS aims to publish all main 2021 Census data on the population of Wales and England within two years of the census. These publications will be released in three phases:

Phase 1 started with the rounded population and household estimates, and will also include topic summaries and area profiles published from autumn 2022. The topic summaries (in order of when they are likely to be published) are:

  • demography and migration
  • ethnic group, national identity, language and religion (including the Welsh language)
  • UK Armed Forces veterans
  • housing
  • labour marker and travel to work
  • sexual orientation and gender identity
  • education
  • health, disability and unpaid care

Phase 2 is from winter 2022 to early 2023. It will include the publication of statistical commentaries alongside topic summary data, multivariate data for the usual resident population base and the release of data on the short-term resident population.

Phase 3 will begin in spring 2023. This phase will include data for alternative population bases, small populations, detailed migration data, ‘flow’ data and microdata samples.

For more information please see the ONS release plans.

ONS population statistics updates

The ONS has published an article and a blog giving an update on the development of the dynamic population model (DPM) (Office for National Statistics). This new approach uses statistical modelling and administrative data sources to provide more frequent, relevant, and timely population statistics.

How is the dynamic population model different to the current mid-year estimates?

The existing method for estimating population suffers from increasing error the further we move away from the date of the previous census. However, the DPM addresses this problem by combining independent data on population with changes from births, deaths, migration, and demographic trends.

The ONS has also published a guide to population statistics and sources (Office for National Statistics). The guide includes references to the different types of population estimates that are planned for publication in 2022 and 2023, including the mid-year estimates of the population for 2021, which are scheduled to be published in November, and re-based mid-2012 to mid-2020 population estimates, which are scheduled to be published in early 2023.

Welsh language statistics

For information on Welsh language statistics, please see the Statistics Wales quarterly update.


Martin Parry

Telephone: 0300 025 0373



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