How much marks required in 12th for applying iit test

A minimum of 75% aggregate  marks across 5 subjects namely PCM and two languages, is mandatory to be eligible for JEE advanced, the candidate can also be allowed if he is tiop 20 percentile.

Hence, you are required to manage efectivelyboth JEE and Class 12th board exams.

There are factors well to look out for qualifications into JEEadvanced for securing seats into IITs:

https://engineering.careers360.com/articles/jee-advanced-eligibility-criteria

Some great preparation tips shared for you to secure more than 75% in class 12th:

https://engineering.careers360.com/articles/how-prepare-for-jee-main-and-class-12th-board-exams

You should get 75% marks in your board exam or you should be top 20 percentile to be eligible to apply for IITs.

Good Luck!!