Your JEE Main score of 76% is a crucial factor, but admission into the Computer Science (CS) branch at IITs depends on several other criteria:

1. Rank and Cutoffs : CS branches typically have higher cutoffs due to high demand. Your rank relative to others applying for CS will determine your chances.

2. Category : Reservation categories (like SC, ST, OBC) may have lower cutoffs, improving your chances if applicable.

3. Other Factors : Some IITs consider board exam performance and interview rounds.

While a 76% score is a good starting point, check the previous year's cutoffs and consult with IIT counseling services for a clearer understanding of your admission prospects in the CS branch based on your rank and other factors.

hope this helps you!!