Age in seconds

Your age in seconds. A billion seconds is about 31 years and 8 months, which is a birthday worth marking and almost nobody does.

The numbers get large quickly and are more interesting than they sound. A year is roughly 31.5 million seconds, so most adults are somewhere between one and two billion. The billion-second mark falls at 31 years, 251 days — a genuinely arbitrary milestone that has the advantage of being precise, unlike a birthday, which quietly ignores the six hours a year that make leap days necessary. Worth knowing that this counts elapsed days times 86,400 and does not account for leap seconds; there have been 27 of them since 1972, so a strict count of SI seconds since your birth is 27 higher than any calendar-based figure.