Vishal,

The cutoff and qualification details for bit mesra is done through JOSAA counseling system. It totally depends on your JEE main rank.

For qualifying bit mesra ; you have to score 75% in total if you're a part of CBSE and ISC boards. But if you're a part of different state than you have to be within 20 percentile rank of your state board. For reservation categories there is some relaxation as per the state board criterias.

The cutoff for joining bit mesra is different for different branches. For more details for cutoff on each branch visit

https://www.careers360.com/university/birla-institute-of-technology-mesra

Hope this helps!