What is a SAT percentile
Each section has a range of 200-800; which ranges anywhere between 400-1600. If you get the 99th percentile, then it means that you stand above 99% of the competition. Percentile ranges from 1-99. Your percentile is an indicator of where you stand amongst all the test takers. Also the percentile does not mean that you got 99 % marks.
The highest composite score for the SAT is 800+800, or 1600. The average score is 1000. Your section scores are the individual scores for the two main sections of the SAT: reading/writing and math. Each of these sections is scored out of 800, and they are added together to get your overall score.
Conversion to Scaled Score
SAT raw score is converted to a scaled score of 200 to 800 points, the score you see on your score report.