To calculate your rank with the help of your percentile, we should use the formula:(100-your total percentile)*869010/100. Going by this formula, your rank will be 84902 Now, this is for the January session. If the no. of Candidates appearing for JEE Mains April session is increased to 12,00,000 then your final rank is calculated using the formula:(100 - your total score) X 12,00,000/100. Going by previous years data for NIT Himachal Pradesh, with this rank, it is difficult for CSE branch because 3024 was the last rank. Your son has to write JEE April session. Check the previous cut offs once by visiting our page: https://engineering.careers360.com/articles/jee-main-cutoff-for-nit-hamirpur To predict the colleges for this rank, visit our college predictor link available at https://engineering.careers360.com/jee-main-college-predictor