What does 'percentile' mean?
If you've looked around in your stats page much, you've probably noticed a percentage number for each game type that says 'percentile.' What does that mean?
Percentile is a term used in statistics to describe the percentage of a group that falls at or below a certain level. The measure in this case, is the person's rating. In the above picture, the member is at the 42nd percentile. The percentile number here means that 42.7% of members on Chess.com have a rating that is equal to, or below this member's rating.
For a clearer example, Hikaru's blitz percentile is 100%, because 100% of everyone on Chess.com has a blitz rating equal to, or below Hikaru's rating!
The important thing to remember is that this number is describing the number of members who are equal to or below the person's rating. Hikaru is at 100% because no one is higher than his rating. This puts 100% of everyone at equal to, or below him.
Another way to think of the percentile is as the percent of people on Chess.com who you are better than!