Title: Birthday
Content:  In the Gregorian calendar (a common solar calendar), February in a leap year has 29 days instead of the usual 28, so the year lasts 366 days instead of the usual 365. A person born on February 29 may be called a "leapling" or a "leaper". In common years, they usually celebrate their birthdays on February 28. In some situations, March 1 is used as the birthday in a non-leap year since it is the day following February 28. Technically, a leapling will have fewer birthday anniversaries than their age in years. This phenomenon is exploited when a person claims to be only a quarter of their actual age, by counting their leap-year birthday anniversaries only. In Gilbert and Sullivan's 1879 comic opera The Pirates of Penzance, Frederic the pirate apprentice discovers that he is bound to serve the pirates until his 21st birthday rather than until his 21st year. For legal purposes, legal birthdays depend on how local laws count time intervals.
Title: February 29
Content: As a Christian feast day: ; Saint John Cassian ; February 29 in the Orthodox church ; Rare Disease Day (in leap years; celebrated in common years on February 28) ; Bachelor's Day (Ireland, United Kingdom) 
Title: Birthday
Content:   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 religions celebrate the birth of their founders or religious figures with special holidays (e.g. Christmas, Mawlid, Buddha's Birthday, and Krishna Janmashtami). There is a distinction between birthday and birthdate: The former, other than February 29, occurs each year (e.g. January 15), while the latter is the exact date a person was born (e.g. January 15, 2001).
Title: Leap year
Content:  A person born on February 29 may be called a "leapling" or a "leaper". In common years, they usually celebrate their birthdays on February 28. In some situations, March 1 is used as the birthday in a non-leap year, since it is the day following February 28. Technically, a leapling will have fewer birthday anniversaries than their age in years. This phenomenon is exploited when a person claims to be only a quarter of their actual age, by counting their leap-year birthday anniversaries only: for example, in Gilbert and Sullivan's 1879 comic opera The Pirates of Penzance, Frederic the pirate apprentice discovers that he is bound to serve the pirates until his 21st birthday (that is, when he turns 88 years old, since 1900 was not a leap year) rather than until his 21st year. For legal purposes, legal birthdays depend on how local laws count time intervals.
Title: Leap year
Content: 1) Where a person has been born on February 29 in a leap year, the relevant anniversary in any year other than a leap year shall be taken to be March 1. ; 2) This section shall apply only where the relevant anniversary falls on a date after the date of commencement of this Ordinance." Since 1990 non-retroactively, Hong Kong considers the legal birthday of a leapling March 1 in common years: "# The time at which a person attains a particular age expressed in years shall be the commencement of the anniversary corresponding to the date of [their] birth.
Title: Birthday
Content:  birth. An individual's Beddian birthday, named in tribute to firefighter Bobby Beddia, occurs during the year that their age matches the last two digits of the year they were born. In many cultures and jurisdictions, if a person's real birthday is not known (for example, if they are an orphan), then their birthday may be adopted or assigned to a specific day of the year, such as January 1. The birthday of Jesus is celebrated at Christmas. Racehorses are reckoned to become one year old in the year following their birth on the first of January in the Northern Hemisphere and the first of August in the Southern Hemisphere.
Title: Birthday
Content:  Christmas, New Year's Day and fixed-date holidays such as July 4 in the US. In the United States between 1973 and 1999, September 16 is the most common birthday in the United States and December 25 the least common birthday (other than February 29, because of leap years). In 2011, October 5 and 6 were reported as the most frequently occurring birthdays. In New Zealand, the most common birthday is September 29, and the least common birthday is December 25. The ten most common birthdays all fall within a thirteen-day period, between September 22 and October 4. The ten least common birthdays (other than February 29) are December 24–27, January 
Title: February 29
Content:  February 29, also known as leap day or leap year day, is a date added to leap years. A leap day is added in various solar calendars (calendars based on the Earth's revolution around the Sun), including the Gregorian calendar standard in most of the world. Lunisolar calendars (whose months are based on the phases of the Moon) instead add a leap or intercalary month. It is the 60th day of a leap year in the Gregorian calendar, and 306 days remain until the end of the leap year. It is also the last day of February on leap years.
Title: Leap year
Content:  Mart. shifted the latter day to February 25 in leap years, with the Vigil of St. Matthias shifting from February 23 to the leap day of February 24. This shift did not take place in pre-Reformation Norway and Iceland; Pope Alexander III ruled that either practice was lawful (Liber Extra, 5. 40. 14. 1). Other feasts normally falling on February 25–28 in common years are also shifted to the following day in a leap year (although they would be on the same day according to the Roman notation). The practice is still observed by those who use the older calendars.
Title: Birthday
Content: Jesus Christ's traditional birthday is celebrated as Christmas Eve or Christmas Day around the world, on December 24 or 25, respectively. As some Eastern churches use the Julian calendar, December 25 will fall on January 7 in the Gregorian calendar. These dates are traditional and have no connection with the actual birthday date of Jesus, which is not recorded in the Gospels. ; Similarly, the birthdays of the Virgin Mary and John the Baptist are liturgically celebrated on September 8 and June 24, especially in the Roman Catholic and Eastern Orthodox traditions (although for those Eastern Orthodox churches using the 

Question: when do you celebrate birthday if born on feb 29?
Answer: February 29.
February 28.
March 1.