Percentile Score tells you the number of candidates (in percentage) who have ranks below your rank.
Example,
Suppose there are 4 students A, B, C, and D who applied for a test.
A secured 60/100
B secured 55/100
C secured 78/100
D secured 65/100
So ranks would be like -
1st C
2nd D
3rd A
4th B
FOR A,
Number of students securing ranks below A = 1 (i.e B)
Total number of students = 4
Percentile of A = 1/4 X 100 = 25
FOR B,
Number of students securing ranks below B = 0
Total number of students = 4
Percentile of B = 0/4 X 100 = 0
For C,
Number of students securing ranks below C = 3 (A, B, D)
Total number of students = 4
Percentile of A = 3/4 X 100 = 75
For D,
Number of students securing ranks below D = 2 (A, B)
Total number of students = 4
Percentile of A = 2/4 X 100 = 50
This was just an example. In actual scenario, suppose there are 15,00,000 (15 lakhs) students who appeared in NEET and you got 700 rank, your percentile would be -
(15 lakhs - 700)/15 lakhs X 100
= 14,99,300/15 lakhs X 100
= 99.9533333
Hope you have understood.
Thank you.

Hello. The results are based on percentile score which is done for the first time in JEE MAINS 2019 exam. The percentile scores indicates the percentage of candidates that have scored equal to or below that particular percentile in that exam. Therefore the topper will get 100 percentile most probably. The marks obtained between the highest and lowest is also converted to appropriate percentile. This is done so that there is normalisation of the marks and no student is disadvantaged or benefitted from a particular question paper set or the session for which they appeared. The percentile scores for the total raw score for all the 4 sessions (in january exam) will be merged and that is your NTA score. This will be used for compilation of result and preparation of the Overall merit list after the April 2019 exam results.

For further information about how the percentile is calculated and how results will be prepared check the below link.

Https://engineering.careers360.com/articles/jee-main-normalisation-process-how-scores-are-calculated

Also check out the official Jee mains website.

Https://jeemain.nic.in/webinfo/Public/Home.aspx

Hope this helps. For any other questions please feel free to comment down below.

Good luck!