If you need to generate a dynamic series of dates with a formula that increase by one month from a single start date, you can do so with a formula that uses the DAY, MONTH, YEAR, and DATE functions.
How the formula...

If you need to test two dates to see they both have the same month and year, you can do so with a simple formula that uses the MONTH and YEAR functions.
How the formula works
In the example, the formula in cell D6...

To add a given number of years to a date, you can use a formula based on the DATE function, with help from the YEAR, MONTH, and DAY functions.
In the example shown, the formula in D5 is:
=DATE(YEAR(B5)+C5,MONTH(B5),...

If you want to calculate the fiscal quarter from a date, and the fiscal quarter starts in a month other than January, you can use a formula based on the CHOOSE function.
Note: if you just need to calculate a "normal"...

If you need to extract the month from a date, you can use the MONTH function. In the generic form of the formula above, the date must be in a form that Excel recognizes as a valid date.
Here's how the formula works:...

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 shown, the formula in cell C5 is:
=MONTH(DATE(YEAR(B5),2,29...

If you need to test two dates to see they both have the same month, you can do so with a simple formula that uses the MONTH function.
How the formula works
In the example, the formula in cell D6 contains this formula...

If you need to get the month name (i.e. January, February, March, etc.) from a date, you have several options depending on your needs.
Do you just want to display the month name?
If you only want to display a month...

If you want to calculate the quarter (i.e. 1,2,3,4) from a date, you can use the ROUNDUP function together with MONTH.
In the example shown, the formula in cell C5 is:
=ROUNDUP(MONTH(B5)/3,0)
How this formula works...

If need to generate a dynamic series of dates with a formula that increase by one year from a single start date, you can do so with a formula that uses the DAY, MONTH, YEAR, and DATE functions.
How the formula works...