Dear Sundar, if you fall under General Category, you should score a minimum aggregate of 75% in your Class 12 and born after October 1st, 1993. If you fall under SC/ST/PWD, then 65% is the required aggregate and born after October 1st, 1998. Admissions into IIST are based on JEE Mains and JEE Advanced.  Registrations for IIST B.Tech will open from May 22nd online and will close by June 5th. Based on your JEE Advanced marks, the ranking list will be allotted during the 3rd week of June. And you can fill in your choices of colleges between 3rd week to 4th week of June. The seats will be allocated during 4th week of June to 4th week of July. For more information, please visit our page: https://engineering.careers360.com/articles/iist-btech-admission