Template:Birth based on age as of date

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For a person whose date of birth is unknown, this template estimates the person's birth year and current age based on a given age at a certain date. This is useful when a reliable source states only their age at the time of publication.

Syntax

Typical use

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

Code:

{{birth based on age as of date|50|2024|12|15}}

Result:

1973 or 1974 (age 51–52)

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.

If only the publication year for a source is known, the "day" and "month" fields can be omitted.

No age

In some contexts—like the lead sentence of a biography—it may be desirable to show only the birth year, and not a person’s age. To suppress the age field, set |noage=1:

Code:

{{birth based on age as of date|50|2024|12|15|noage=1|slash=y}}

Result:

1973/1974

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

Separator

In general, the two possible birth years should be written out as: 1950 or 1951. In contexts which are tight for space, the separator between the two possible years should be a slash: 1950/1951.

To use the / separator, add |slash=y.

Code:

{{birth based on age as of date|50|2024|12|15|slash=y}}

Result:

1973/1974 (age 51–52)

Code:

{{birth based on age as of date|50|2024|12|15|mos=1}}

Result:

1973 or 1974 (age 51–52)

Examples

If, for example, a reference dated July 4, 2024 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|2024|July|4}}

The following examples are for a person reported as being 50 years old in 2025

Template code Result {{birth based on age as of date | 50 | 2025 | 01 | 15}} 1974 or 1975 (age 51) {{birth based on age as of date | 50 | 2025 | January | 15}} 1974 or 1975 (age 51) {{birth based on age as of date | 50 | 2025 | 12 | 31}} 1974 or 1975 (age 50–51) {{birth based on age as of date | 50 | 2025 | Jan | 1}} 1974 or 1975 (age 51–52) {{birth based on age as of date | 50 | 2025 | 12 | 31 | noage=1}} 1974 or 1975 {{birth based on age as of date | 50 | 2025 | Jan | 1 | noage=1}} 1974 or 1975 {{birth based on age as of date | 50 | 2025 | January}} 1974 or 1975 (age 50–52) {{birth based on age as of date | 50 | 2025 | Jan}} 1974 or 1975 (age 50–52) {{birth based on age as of date | 50 | 2025 | 12}} 1974 or 1975 (age 50–51) {{birth based on age as of date | 50 | 2025}} 1974 or 1975 (age 50–52)

This template calculates the birth year and current age based on the age as of a date.

Template parameters[Edit template data]

This template prefers inline formatting of parameters.

Parameter		Description	Type	Status
Age	1	Age of subject at date of reference's publication. Example 55	Number	required
Year	2	Year of publication of reference. Example 1950	Number	required
Month	3	Month of publication of reference. Example 8 or August	String	suggested
Day	4	Day of publication of reference. Example 21	Number	suggested
Hide age	noage	Set to a value of 1 to display year of birth without the age. Example 1	Number	optional
Slash separator	slash	Set to 'y' to separate years with a '/' for tight spaces (eg, table cells)	Unknown	optional
Or separator	mos	Set to a value of 1 to replace the '/' separator with ' or ' in compliance with [[WP:APPROXDATE]]. Example 1	Number	deprecated

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