Age of person

Status: This standard was approved as a departmental standard on May 22, 2007.


Age refers to the age of a person (or subject) of interest at last birthday (or relative to a specified, well-defined reference date).

Person refers to an individual and is the unit of analysis for most social statistics programs.


'Age of person' is usually derived. It is usually calculated using the person's date of birth and the date of interview or other well-defined reference date.

Conformity to relevant internationally recognized standards

This standard conforms to the recommendations for censuses contained in the United Nations' "Principles and Recommendations for Population and Housing Censuses, Revision 3", 2017. The UN recommendations define age as "the interval of time between the date of birth and the date of the census, expressed in completed solar years". This is equivalent to this standard's definition of age as "age at last birthday". In addition, the UN recommends calculating age from date of birth rather than asking it directly. This derivation of age is recognized in this standard as the usual practice. Use of date of birth, as noted in the UN Principles, allows age to be calculated precisely, avoiding rounding by respondents and potential misunderstanding as to whether the age wanted is that of the last birthday, the next birthday or the nearest birthday. Finally, the UN's "Demographic Yearbook 2019" uses five-year age groupings with the same boundaries as those presented in this standard. The only difference is that sometimes children under the age of 1 year are reported in a separate category.

The "Conference of European Statisticians Recommendations for the 2020 Censuses of Population and Housing" also recommends that information on age be obtained by collecting information on date of birth.


  • Decimal number January 01, 2018 to current
  • 'Age' is expressed in individual years of age ranging from 0 (less than one year) to the maximum number on the file. May 22, 2007 to current


Relation to previous version

  • Age of person May 22, 2007 to current

    A classification by single years of age has been added. In the classification of five year age groups, the top five categories in the previous classification have been collapsed into one category. These top categories were collapsed to reflect the population numbers in these categories and the reliability of the data in this part of the age range. The classification Age by life cycle groupings, which was part of the previous standard, is no longer recognized as part of the standard for age.

  • Age by Life Cycle Groupings July 15, 1998 to May 21, 2007

    This standard was replaced by the 'Age of person' as of May 22, 2007.

  • Age July 15, 1998 to May 21, 2007

    This standard was replaced by the 'Age of person' as of May 22, 2007.

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