DateTime Format In SQL

Question

pls Resolve this Issue..

 

DECLARE @Stdate varchar(20)

SET @Stdate = CONVERT(VARCHAR(20), '31/03/2016', 111)

SELECT (DATEADD(MONTH, 12 , @Stdate)) AS EndDate

 

Error

 

Msg 242, Level 16, State 3, Line 34

The conversion of a varchar data type to a datetime data type resulted in an out-of-range value.