Leap years almost always occur every four years, (i.e. in years that are divisible by 4). The only exceptions to this is that years that are evenly divisible by 100 are not leap years, unless they are also divisible by 400.

So this means that the years 1700, 1800, 1900, etc., were not leap years, but the year 2000 was, and the years 2400 and 2800 will be.

en.wikipedia.org/wiki/Leap_year

A leap year is a calendar year containing one additional day added to keep the
calendar year ..... The observed and calculated versions of the Islamic calendar
do not have regular leap days, even th...

stackoverflow.com/questions/725098/leap-year-calculation

In order to find leap years, why must the year be indivisible by 100 and ... The
length of a year is (more or less) 365.242196 days. So we have to ...

www.wikihow.com/Calculate-Leap-Years

How to Calculate Leap Years. To calculate if a year is a leap year is easy. Start
off using the year you want to calculate.

www.timeanddate.com/date/leapyear.html

Feb 29, 2016 ... Is 2016 a leap year? A leap year has 366 days, as opposed to a common year,
which has 365. We add a leap day – February 29 – nearly every ...

exceljet.net/formula/year-is-a-leap-year

If you want to test whether the year of a certain date is a leap year, you can use a
formula that uses the MONTH, YEAR, and DATE functions. In the example ...

www.onlineconversion.com/leapyear.htm

Easily determine if a year is a leapyear or not. ... Leap Year Calculator. You do
not have JavaScript enabled. The conversions ... Check For Leap Year: Year: is ...

www.mathsisfun.com/leap-years.html

A Leap Year has 366 days (the extra day is the 29th of February). ... Leap Years
are any year that can be evenly divided by 4 (such as 2012, 2016, etc). not ...

www.reference.com/science/calculate-leap-years-30ca8f8823b606ad

The formula for calculating whether a year is a leap year or not is as follows: if a
year can be evenly divided by 4 (such as 2012), then it is a leap year unless it ...

leapyearday.com/content/leap-year-calculator

Is it a leap year? What about in 1900? Or 2100? Get your Leap Year facts straight
with this Leap Year calculator. Just enter the year you are interested in and the ...