hello,

if you don't have reservation category then your rank has to be below 100 to get top IIT campus.

if you have single reservation category then closing cutoff rank will be 1000-1500.

if you have combo  reservation category like OBC-NCL -PwD or ST-PWD or SC-PWD then maximum rank cutoff will go upto 5k.

in terms of marks, you have to score 90% of total marks to get top 100 rank and get into best campus.

do study hard and practice well. Don't worry about marks. if you give your best in practice, you can make out to best.

for previous year cutoff for different IIT campus, please visit the link :- https://cache.careers360.mobi/media/uploads/froala_editor/files/JAM2020_cutoffRound1_DXckvvO.pdf

Hope it helps!