Besides calculating the age of the person, the benefit of using this template, is to allow for the inclusion of hidden metadata to be used, indexed or searched by software tools.
{{Birth-date and age| birth date | wikitext to display in place of 'birth date'. Like the right hand parameter in a wikilink, this could be alternate text, links, templates etc. }}
Birth-date and age examples (colors for emphasis only):
Month first format: Sample below displays April 12, 1941 (1941-04-12) (age 83), with invisible microformat date: 1941-04-12
{{birth-date and age|April 12, 1941}}
Day first format: Sample below displays 12 April 1941 (1941-04-12) (age 83), with invisible microformat date: 1941-04-12
{{Birth-date and age| 12 April 1941 }}
Year only, year and month only: Sample below displays 1941 (1941) (age 83), with invisible microformat date: 1941
{{Birth-date and age | 1941 }}
Demo of ISO date, as well as alternate displays. Sample below displays Twelfth of April, 1941 (1941-04-12) (age 83), with invisible microformat date: 1941-04-12
{{Birth-date and age| 1941-04-12 | Twelfth of April, 1941}}
Birth date. May be year only, year and month, year month and day, expressed in natural formats: eg: 24 August 1953, 1955-08-25, Sunday, December 7, 1941. If parameter three is not specified, the birth date is displayed in exactly this format. This value as well as parameter 2 may not include links. If links or templates that do not evaluate as recognizable dates are desired, use parameter 2.
–
(optional)
2
The birth date to display. This may include links or templates, or any combination of them, and overrides parameter 1.
parm 1
(optional)
bce
If birth date is BC, set to "b".
–
(optional)
gregorian
If Julian date is used, this parameter is required. The date provided is used for emitting the correct microformat translation of the birth date.
parm 1
(optional)
dt
This value if present is the ISO8601 value emitted to indicate microformat birth date. It overrides any calculated value.
Combines functions of {{Birth date}}, {{birth-date}}, {{birth date and age}}, {{birth year and age}}, {{death date}}, {{death-date}}, {{death date and age}}, and {{death year and age}}.
To display approximate birth year and current age given a particular date (e.g. when a dated reference mentions the age of a person), only works for living people.