How to Calculate GATE Percentile ?

Use the Formula,

P=((T-R)/T) x 100 

where P=percentile.

T=Total candidates appeared for the exam.

R=All India Rank.

If 

If your All India Rank (R) = 200,

Total candidates appeared for the exam (T) =16425,

P=(16425-200) / 16425) x 100 

Your Percentile (P) =  98.78%

The All India Rank, Number of students everything matters a lot when it comes to percentile calculation.

GOOD LUCK