Age in ten year groups (AGE10P)

This variable records a person’s age in 10 year groups. Infants under one year are recorded as zero years old and therefore appear in the '0-9 years' category. 

Age is also available as single years from 0 to 115 (age (AGEP)) and in five year groups (age in five year groups (AGE5P). 

All persons

Age is calculated from the date of birth when it is provided; otherwise, the stated age is used. When both are given, date of birth is used to calculate age, unless an error in the date of birth is found. Age is recorded in whole years only. 

If no age information is provided, it is imputed using other responses on the form and population age patterns. Imputation is also applied when reported ages are outside the valid range or conflict with other data, such as relationship details.

A question on age has been asked in every Census since 1911. From 2006, people could give either their date of birth or their age in years. 

In 2021, the question was updated to request both date of birth and age. The online form was redesigned to collect date of birth first, with a mark box for when it is not known. This change improved the accuracy of age data. 

There have been no changes for the 2026 Census.