TechInfoDepot:Age calculation templates

Wikipedia uses several templates that self-update every day to keep date and age information current. These are very useful for a dynamic online encyclopedia and save users from having to regularly update that kind of information. However, when using this kind of template, a few things should be kept in mind.

Mentioning "as of" date
In mirrored versions of the site as well as print versions, such statistics will immediately become inaccurate. As such, they should always be accompanied by a note to indicate the date at which it was last correct. The note itself can be made self-updating along with the age calculation template by adding  "as of " . For more information about self-updating as-of dates, see TechInfoDepot:As of.

When to use templates vs. fixed text
Some of these templates, such as add useful metadata to biography pages, and should be used in the person's infobox or when the information is first needed in the prose. This is true whether the information updates or is fixed.

In lists, however, they should only be used where the self-updating feature is needed. Some of these templates can be complex, and will greatly add to the loading time of a page if used many times. For example, in an article like List of Canadian Prime Ministers by time in office, the template is only used for the incumbent prime minister, and fixed numbers are used for all past prime ministers.

Examples
Common age calculation templates include the following. Check similar templates to make sure you are using the right one for your article.

Age

 * Age
 * Age nts – for use in sortable tables
 * Age in days
 * Age in days nts – for use in sortable tables
 * Age in years and days
 * Age in years and days textual version - for when you want to use a period in years and days in text
 * Age in months
 * Age in weeks
 * Age in weeks and days
 * Age in years, months, weeks and days
 * Age for infant – displays months and days up to one year, years and months up to three years, and years beyond

Dates

 * Birth date
 * Birth-date – works with "fuzzy" or ambiguous dates
 * Birth date and age
 * Birth date and age2 – calculates age at a specified date
 * – used when a reference mentions the age of a person as of the date of the reference's publication
 * Birth year and age
 * Death date
 * Death date and age
 * Death year and age
 * BirthDeathAge – combines the functionality of the above six birth and death templates