Hot to get days in a month in SQL Server?

I want to get total days in a month for given date in SQL Server, whatever I know, already tried but nothing work.

I don't thing there is any build in function, if any please suggest me or any way to achieve this.

Add one month to date and get date difference between your date and one month added date

Select DATEDIFF(day, getdate(), dateadd(month, 1, getdate()))