A half-birthday is a day approximately six months before or after the anniversary of a person's birth. It is sometimes marked by people whose
birthday
A birthday is the anniversary of the birth of a person, or figuratively of an institution. Birthdays of people are celebrated in numerous cultures, often with birthday gifts, birthday cards, a birthday party, or a rite of passage.
Many re ...
falls near major holidays, the celebration of which may overshadow celebration of the birthday. It may also be marked by students whose birthday does not occur during the regular school year; a half-birthday allows a celebration with friends at school, with half a cake.
Calculation
There are two ways to calculate half-birthdays.
The easier but potentially less precise method is to take the number of the date of the birthday and advance the month by six: e.g. December 5 becomes June 5. Because not all months have the same number of days, this method does not always work – for example, six months after an August 30 birthday would be
February 30
Several non-standard dates are used in calendars. Some are used sarcastically, some for scientific or mathematical purposes, and some for exceptional or fictional calendars.
January 0
January 0 or 0 January is an alternative name for December 3 ...
, which is nonexistent in the
Gregorian calendar
The Gregorian calendar is the calendar used in most parts of the world. It was introduced in October 1582 by Pope Gregory XIII as a modification of, and replacement for, the Julian calendar. The principal change was to space leap years dif ...
.
The more precise method is to add or subtract half the number of days in a year to the birth date. In the case of a common year, this would be 182.5 days. In leap years, the number of days would be 183. This method would lead to a March 1 or February 29 half-birthday for an August 31 birthday, depending on whether it's a leap year.
In the U.S., some tax-related penalties are related to half-years, such as a 10% penalty for making an early withdrawal from an
IRA
Ira or IRA may refer to:
*Ira (name), a Hebrew, Sanskrit, Russian or Finnish language personal name
*Ira (surname), a rare Estonian and some other language family name
*Iran, UNDP code IRA
Law
*Indian Reorganization Act of 1934, US, on status of ...
before age 59½. The federal government defines the half-year as being "six calendar months" after the anniversary of birth, regardless of what day of the month this produces.
Cornell Legal Information Institute: "Distributions commencing during an employee's lifetime"
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In many states in the U.S., the minimum age to obtain a learner permit occurs on a half-birthday, such as 14½ in Idaho
Idaho ( ) is a state in the Pacific Northwest region of the Western United States. To the north, it shares a small portion of the Canada–United States border with the province of British Columbia. It borders the states of Montana and Wyomi ...
, 14 years and eight months in Michigan
Michigan () is a U.S. state, state in the Great Lakes region, Great Lakes region of the Upper Midwest, upper Midwestern United States. With a population of nearly 10.12 million and an area of nearly , Michigan is the List of U.S. states and ...
, 15½ in California
California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the m ...
, and 15 years and nine months in Maryland
Maryland ( ) is a state in the Mid-Atlantic region of the United States. It shares borders with Virginia, West Virginia, and the District of Columbia to its south and west; Pennsylvania to its north; and Delaware and the Atlantic Ocean to ...
. The same is true for receiving a restricted license when a minor in many states.
Popular culture
At least three children's books have been written about half-birthdays:
*
*
*
Mentions in TV Series
* He brought gelato to every birthday. And every half-birthday. Which all three of these kids now think is an actual thing.
See also
* Unbirthday
References
{{DEFAULTSORT:Half-Birthday
Birthdays