Countdown
A live countdown to the next February 29th, calculated from the real rule — not just "every 4 years," which is only an approximation.
The actual Gregorian rule: a year is a leap year if divisible by 4, unless it's also divisible by 100 — in which case it's not a leap year, unless it's also divisible by 400, in which case it is after all. The year 2000 was a leap year (divisible by 400); 1900 and 2100 are not (divisible by 100 but not 400). This three-tier rule exists because a real solar year is about 365.2422 days, not exactly 365.25, and the extra correction keeps the calendar from drifting off by a full day every few centuries. Check any specific year with the Leap Years List or the year-by-year leap checker pages.
Someone born on a leap day technically only has a "real" birthday once every four years (or longer, around century boundaries) — most either celebrate on February 28th or March 1st in non-leap years, a choice with no official rule attached, purely personal preference.
Related
Every year in range, marked and linked to its own page.
For everyone else, whose birthday isn't quite this rare.
What day of the week any date falls on.