Percentile Calculator
Calculate percentile ranks and find values at specific percentiles in your dataset. Essential for test score analysis, data comparison, and statistical reporting.
Step-by-Step Calculation
Understanding Percentiles
What is a Percentile?
A percentile indicates the relative standing of a value in a dataset. The Nth percentile is the value below which N% of the data falls. For example, if you score in the 75th percentile, you performed better than 75% of all test takers.
When to Use This Calculator
- Analyzing standardized test scores (SAT, GRE, etc.)
- Understanding growth charts and medical measurements
- Comparing performance in surveys or assessments
- Identifying data distribution and outliers
- Setting performance targets or thresholds
Common Percentiles
- 25th percentile (Q1): First quartile, lower 25% of data
- 50th percentile (Median): Middle value, half above/half below
- 75th percentile (Q3): Third quartile, upper 25% of data
- 90th percentile: Top 10% of data
- 99th percentile: Top 1% of data
Real-World Example
If you score 1200 on the SAT and that's the 75th percentile, it means you scored higher than 75% of all test takers. Out of 100 students, approximately 75 scored lower and 25 scored higher than you.
Common Mistakes
- Confusing percentile with percentage score (50th percentile ≠ 50% correct)
- Using percentiles with very small sample sizes (less accurate)
- Assuming percentiles are evenly distributed (depends on data distribution)
Educational Purpose Disclaimer
This calculator is provided for educational purposes only. Results should not be used as the sole basis for critical decisions. Always verify important calculations independently and consult qualified professionals when needed.