Hi Mhd, 

You cannot calculate the percentile with your marks. Scores are absolute measurement, while percentile is a relative measurement. 

Percentile is [ (the number of students scoring below you/equal to you) / (total number of students) ] * 100

For calculating the percentile in AIIMS exam, they take into consideration the individual ranking, average score of all the students who appeared for the exam, the average score of the students who appeared in your batch, etc. 

This system is also to justify any biased grading that might occur due to different batches and different papers. 

All The Best.