Percentile Calculator – Statistical Percentile
Calculate percentiles and understand data distribution
Table of Contents
How to Use
- Enter your data set as comma or space-separated numbers
- Enter the percentile you want to calculate (0-100)
- Click calculate to find the percentile value
- View the value and its position in the sorted data
What is a Percentile?
A percentile is a measure used in statistics indicating the value below which a given percentage of observations in a group of observations falls. For example, the 50th percentile (median) is the value below which 50% of the observations may be found.
Percentiles are commonly used in standardized testing, growth charts, and data analysis to understand relative standing within a dataset.
Common Percentiles
- 25th percentile (Q1): First quartile - 25% of data falls below this value
- 50th percentile (Q2): Median - half of the data falls below this value
- 75th percentile (Q3): Third quartile - 75% of data falls below this value
- 90th percentile: Often used to identify high performers or outliers
- 99th percentile: Represents the top 1% of values
Applications of Percentiles
- Standardized test scores (SAT, GRE, etc.)
- Growth charts for children's height and weight
- Income distribution analysis
- Performance benchmarking
- Quality control and process improvement
- Medical reference ranges
How to Interpret Percentiles
If a value is at the 80th percentile, it means that 80% of the values in the dataset are below this value, and 20% are above it. Higher percentiles indicate higher relative position in the dataset.
Frequently Asked Questions
- What's the difference between percentile and percentage?
- A percentage is a proportion out of 100, while a percentile indicates the value below which a given percentage of observations fall. For example, scoring 80% on a test means you got 80% of questions correct, while being at the 80th percentile means you scored better than 80% of test-takers.
- Is the 50th percentile the same as the median?
- Yes, the 50th percentile is exactly the median - the middle value when data is sorted. It's the value below which 50% of observations fall.
- How do you calculate percentiles?
- First, sort the data in ascending order. Then use the formula: rank = (percentile/100) × (n-1), where n is the number of data points. If the rank is not a whole number, interpolate between the two nearest values.
- What does it mean to be in the 99th percentile?
- Being in the 99th percentile means you scored higher than 99% of the population or dataset. Only 1% of values are higher than yours. This typically indicates exceptional performance or an outlier value.