Leap Day is here!

A person who was born on February 29 may be called a "leapling". In non-leap years they may celebrate their birthday on 28 February or 1 March.

For legal purposes, their legal birthdays depend on how different laws count time intervals. In England and Wales the legal birthday of a leapling is 28 February in common years (see Leap Years, above). In Taiwan the legal birthday of a leapling is also February 28 in common years. In both cases, a person born on February 29, 1980 would have legally reached 18 years old on February 28, 1998.

"If a period fixed by weeks, months, and years does not commence from the beginning of a week, month, or year, it ends with the ending of the day which proceeds the day of the last week, month, or year which corresponds to that on which it began to commence. But if there is no corresponding day in the last month, the period ends with the ending of the last day of the last month.^[2]"

There are many instances in children's literature where a person's claim to be only a quarter of their actual age turns out to be based on counting their leap-year birthdays. A similar device is used in the plot of the Gilbert and Sullivan operetta The Pirates of Penzance. Frederic, born on February 29, was apprenticed to a band of pirates until his 21st birthday, meaning that with all the missed birthdays, until he was 84 years old.