Hello aspirant !!

Hope you are doing well.

If by "calculated marks", you mean the expected marks through various unofficial answer keys, and "actual marks" means the marks as per the provisional answer key released by Joint Admission Board on the official site, you have the chance to challenge the provisional answer key before the stipulated date by paying a fee.

The deadlines for doing so are:

Sunday, October 10, 2021, 10:00 IST
to
Monday, October 11, 2021, 17:00 IST

On the day of result, that is, Friday, October 15, 2021 , the Joint Admission Board will release the final answer keys.

However, if you find your marks displayed in the JEE Advanced result to be different from those you calculated from the provisional answer key, you cannot challenge. There might have been some changes in the provisional answer key which would have led to change in your marks.

All the best !!