The good thing about Stamp duty in Karnataka is that the max stamp duty per day is Rs 50 .... Unlike other states where stamp duty is anywhere from Rs 200/cr to Rs 1000/cr... If you trade only 1 lot of the whole day, the stamp duty would be a big component...
For 1 lot of futures(buying 1 lot selling 1lot):
Brokerage would be Rs 40(20+20), STT around Rs 50, Transaction: around Rs 30, Service tax: around: Rs 7 , Stamp duty: Rs 50(max per day)...
But if you trade 1 lot multiple times, the stamp duty will not increase.. So, if you are trading 1 lot 3 times a day, the effective rate for doing 1 lot of nifty will come down to Rs 135 including all charges....
If you are trading multiple lots at a time the breakeven points would be much lesser... For 2 lots breakeven 2.5pnts, 3 lots 2.2pnts, 5 lots 1.97, 10lots 1.78 and so on....
For futures the component that kills active intraday traders has to be STT , STT with us sometimes is 5 times more than actual commissions paid to us for more active intraday traders....
Cheers....