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The number of persons by single year of age and sex for 2011 Census Output areas in England and Wales, mid-2001 to mid-2020. Output Area (OA) estimates – these datasets provide data from mid-2001 to mid-2020 for Output Areas in England and Wales by single year of age (0 to 89 years, 90 years and over) and sex. This is the lowest level of geographic and age/sex disaggregation available for mid-year population estimates.

List of contents

  1. Dataset details and zip file contents.

  2. Dataset dimensions and variables.

  3. Main points about this dataset.

1. Dataset details and zip file contents

Dataset name

Output_Area_Pop_est_2001_05 (.csv format)


Output Area population estimates in England and Wales for years 2001 to 2005

Dataset name

Output_Area_Pop_est_2006_10 (.csv format)


Output Area population estimates in England and Wales for years 2006 to 2010

Dataset name

Output_Area_Pop_est_2011_15 (.csv format)


Output Area population estimates in England and Wales for years 2011 to 2015

Dataset name

Output_Area_Pop_est_2016_20 (.csv format)


Output Area population estimates in England and Wales for years 2016 to 2020

Please note these output area datasets are very large and are designed to be used in statistical and database packages. They cannot be opened fully in most spreadsheet packages because of their size. The same data, but in different formats are available from the main ONS website and from Nomis (2011 to 2020 only).

2. Dataset dimensions and variables

  • Each dataset contains a total of 33,016,256 records.

  • In total there are 181,408 Output Areas (OAs) in England (171,372) and Wales (10,036).

Variables included in the dataset are as follows.

Variable name



Nine-character code for OAs as defined in 2011

Variable name



Sex: Male = '1', Female = '2'

Variable name



Age = '0' to '90'. The '90' group contains ages 90 years and over

Variable name

Mid_2001 – Mid_2020


Final population estimate: for example, Mid_2001 is the estimate for end-June 2001.

3. Main points about this dataset

Output Area (OA) population estimates are provided as supporting information to help users in building estimates for their own bespoke geographic areas. The status of population estimates at different geographic levels is discussed in the statistical bulletin that accompanies the annual release of these data.

These figures are consistent with the published local authority and Lower Layer Super Output Area (LSOA) population estimates for mid-2001 to mid-2020.

OA to higher geography lookup files are available from: Open Geography Portal.

In England and Wales 2011 Census OAs are based on postcodes as at Census Day. The minimum OA size is 40 resident households and 100 resident persons but the recommended size was rather larger at 125 households. These size thresholds meant that unusually small wards and parishes were incorporated into larger OAs.

These data are made available as supporting information to provide users with "building bricks" for producing exact fit or best-fit population estimates for higher levels of geography, and to allow the creation of population estimates for bespoke age groups. Direct use of these OA estimates by single year of age is not recommended as the estimates cannot be guaranteed to be accurate at this level of detail.

The Small Area Population Estimates (including estimates for LSOAs, Middle Layer Super Output Areas, Wards, Parliamentary Constituencies, Primary Care Organisations, Clinical Commissioning Groups and National Parks) were initially intended for publication by five-year age group and sex. The more detailed estimates provided here are intended to enable and encourage further analysis and use of the estimates. Particular caution should be exercised in using estimates at a greater level of disaggregation – for example, for Output Areas, or for single year of age groups, as these would not be expected to have the same level of accuracy as the aggregated estimates.                     

The estimated resident population of an area includes all those people who usually live there, regardless of nationality. Arriving international migrants are included in the usually resident population if they remain in the UK for at least a year. Emigrants are excluded if they remain outside the UK for at least a year. This is consistent with the United Nations definition of a long-term migrant. Armed forces stationed outside of the UK are excluded. Students are taken to be usually resident at their term-time address.

Further advice on the appropriate use of these data can be obtained by emailing or phoning +44 1329 444661 and asking to speak to a statistician.

Source: Population estimates by output areas, electoral, health and other geographies, England and Wales, Office for National Statistics   Data supplier: Population Estimates Unit Population Statistics Division Office for National Statistics Segensworth Road Fareham PO15 5RR email:                                                                                 

Supporting information

These data are supporting information only. However, the Code of Practice for Statistics is observed in the production of all our statistics.

More information can be found in:

Small Area Population Estimates: Summary of methodology review and research update.


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