Hi Laxminarayan !
I have posted the taxcal in excel a month back on citehr.
Go to search option, type 'Tax calculator', press 'Go'.
You will get the posts on tax calculator with attachments which you can download and use.
If you dont find the relevant information, let me know, I will send it to you / repost it.
(the search option is on the top of this page (next to the face with yellow band ! :) )
- Hiten