Wikipedia contains age calculation 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.

Many articles including biography articles contain infoboxes which use these age and date templates.

For example: The article for Benjamin Franklin infobox contains template
{{death date and age|1790|4|17|1706|1|17}}

Results display the date of his death and his age on that date:
April 17, 1790(1790-04-17) (aged 84)

To add this auto-updating template to your user page, use {{totd b}}