=DATE(YEAR(A1),MONTH(A1)+3,DAY(A1))

Note that you may get unexpected results, like when A1 is Nov 30

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Kind regards,

Niek Otten

Microsoft MVP - Excel

"Andrew Lau" <Andrew wrote in message
...
I input the date (A1) cell is 15-Jan-05, how to make the date value(A2)
cell
is plused 3 months, the function is????