How to calculate ARMA[Autoregressive Moving Average Model] in excel?Without using any external addins like NumXL. Explain with an simple example in excel

You do this in Excel by using NumXL. That's why it was created. If you start your question by eliminating the answer, you're out of luck.

Use NumXL, that's what it was created.

Thanks For your reply.But could you let me know what are the steps and how to construct a model using NumXL with a simple example in excel

NumXL 1.58 (BAJA) Overview - YouTube

NumXL - Wikipedia, the free encyclopedia

No use reinventing this wheel, these tutorials are easily found using Google.