Dear Ramdev,
Cut off is the basically minimum marks which an applicant need to secure to be able to qualify the GPAT 2018 Test. Different institutes authorises recommend different GPAT Score for the allotment of  seat process in AICTE approved programs.
The following table is mentioned about cut off according to caste:-
General - 115 (minimum cut off score)
OBC      - 115
SCS.     -90
ST.        -90
PD.       -90


All the Best