- All years divisible by 400 ARE leap years (so, for example, 2000 was indeed a leap year)
- All years divisible by 100 but not by 400 are NOT leap years (so, for example, 1700, 1800, and 1900 were NOT leap years, NOR will 2100 be a leap year)
- All years divisible by 4 but not by 100 ARE leap years (e.g., 2008, 2012, 2016)
- All years not divisible by 4 are NOT leap years (e.g. 2017, 2018, 2019)
See: