Last date of Financial year

Hello

I want to do following.
Financial Year ended on 31st March.

If date is 18th August 2008, Then last date for financial year is 31st March 2009.
IF date is 15th March 2009, Then also last date for financial year is 31st March 2009.

I want formula / function to get last date of financial yera.

Please help.

If by "date" you mean Today then:

=DATE(YEAR(TODAY())+(MONTH(TODAY())>3),3,31)

If by "date" you mean date in another cell, eg A1 then:

=DATE(YEAR(A1)+(MONTH(A1)>3),3,31)