Hello Greetings

 The percentile Scores are calculated By the following Formula

Total Percentile (T1P): 100 X( No. of candidates appeared from the session with raw score EQUAL TO OR LESS than T1 score /Total No. of candidates appeared in the session)

To know the complete Process of Calculation Please follow the Link Given Below

https://jeemain.nic.in/WebInfo/Handler/FileHandler.ashx?i=File&ii=4&iii=Y

Hope this Helps All the best