Articles are placed in this category automatically when either the day, month, or year is invalid in one of the templates related to human birth dates, death dates, and ages. These templates are listed in the navbox below:

Articles should not be placed in this category manually. To remove articles from this category, find the error message, which looks like invalid day, invalid month, or invalid year in the article and fix the error. Note that many errors of this type are caused by vandalism. Check the page history to see if clicking "undo" is better than a manual fix. Common errors in these templates (other than typos) include:

• Parameters in wrong order, for example "20|8|1993". Should always be "year|month|day".
• Month and day transposed, for example "1974|16|01" (year|day|month). Fix by swapping month and day, for example "1974|01|16" (year|month|day)
• Year (and possibly month) of birth is known, but the day of the month is unknown.
  • To show birth year and age for living people, use {{birth year and age}} instead of {{birth date and age}}.
  • To show just the birth year, use {{Birth-date}}.
  • For dead people, use {{Death date and age}}, providing only the birth year (or year and month).
• {{birth date and age}} and {{birth year and age}} should not be used for people who are dead, for example {{birth date and age|1853|05|12}}. Use {{birth date}} or {{birth-date}} instead.

Certain combinations of incomplete dates are not available in the parameter based templates. An alternative template is available which takes a text based date.

• {{birth-date|1962}}
• {{death-date and age|January 1993|25 June 1930}}