How to Check Leap Year in PowerShell

Tagged: PowerShell

Introduction#

In this blog post, we will walk through how to check leap year in PowerShell.

Solution#

Using System.DateTime Class from .NET Framework#

We can use static method from System.DateTime class to check leap year as in following example:

$year = 2024
[System.DateTime]::IsLeapYear($year)

The output of above script is true because 2024 is a leap year. But, if we change the year to 2018, the output will be false.

Using arithmetic and logical operator#

By definition, a leap year must be divisible by 4 unless the year is divisible by 100 as well but not by 400. So, we can create simple algorithm combining arithmetic and logical operator to check leap year as follows:

$year = 4000
$isLeapYear = $year % 4 -eq 0 -and ($year % 100 -ne 0 -or $year % 400 -eq 0)
Write-Host $isLeapYear

The result of above script is true. However, if the year is changed to 4100, the result will be false because even though 4100 is divisible by 4 and 100, it’s not divisible by 400.

Conclusion#

In conclusion, to check leap year in PowerShell we can use IsLeapYear static method from .NET Framework. Besides that, we can also implement simple algorithm from scratch to check leap year.