This template calculates the birth year and current age based on the age as of a date. This is useful when a reference states only their age at the time of the reference's publication.

{{Birth based on age as of date|age|year|month|day}}

The age, year, and day must be supplied as natural numbers; month can be specified as a natural number as well as by name or abbreviation (e.g. "August" or "Aug"). The Gregorian calendar is assumed, with no special support provided for dual dating or the difference between Old Style and New Style dates .

Suppress the age field:

{{Birth based on age as of date|age|year|month|day|noage=1}}

With the "noage=1" option, the month and day can be "1".

For example, if a reference dated July 4, 2023 mentions that someone is 50 years old, that person's birth year and age can be rendered using

{{Birth based on age as of date|50|2023|July|4}}

The following examples use a date which is exactly one year before:
18 డిసెంబరు 2024

Template text Result
{{Birth based on age as of date|50|2023|12|18}} 1972/1973 (age 51)
{{Birth based on age as of date|50|2023|డిసెంబరు|18}} 1972/1973 (age 51)
{{Birth based on age as of date|50|2023|1|15}} 1972/1973 (age 51–52)
{{Birth based on age as of date|50|2023|Nov|5}} 1972/1973 (age 51–52)
{{Birth based on age as of date|50|2023|Nov|5|noage=1}} 1972/1973
{{Birth based on age as of date|50|2023|1|1|noage=1}} 1972/1973