I just stumbled across this on my own. I find that all leap years in the current calendar are multiples of 16. Therefore, to see if a year is a leap year, one need only to divide the year by 16 and see if there is a remainder. If so, the year is not a leap year. If not, the year is a leap year. Note that this only works for dates in the Gregorian calendar, which was created in 1582 AD but was not universally adopted for a few years. So you'll need to know when the country of interest adopted the Gregorian calendar.