A post-election survey released Tuesday said the BJP was set to win a record 253 seats in the Lok Sabha and the Congress just 66, its lowest ever tally.
The BJP-led National Democratic Alliance (NDA) will win in all 303 seats, according to the LensOnNews survey conducted after each polling day during the 10-phase ballot, covering a total of 40,000 voters.
The findings carry a margin of error of three percent.
The Congress-led United Progressive Alliance (UPA) will be left with 89 seats in the Lok Sabha, it said.
It said the impressive wins of the Bharatiya Janata Party will mostly come from Uttar Pradesh, Bihar, Rajasthan and Maharashtra.
The BJP will hold on to their strong position in Gujarat, Madhya Pradesh and Karnataka, it said.
Additionally, the BJP alliance has made significant inroads in states like Tamil Nadu where it had little presence earlier.
The survey said that in Tamil Nadu, the NDA was likely to finish second, ahead of the DMK - the main opposition party - in both vote share and seats.
Likewise in Odisha, the BJP was likely to push aside the Congress to the third place.
Exit polls Monday evening unanimously predicted a victory for the BJP-led NDA from the just ended Lok Sabha election.