Percentile Calculator
Find any percentile from a data set instantly, using the same interpolation method as Excel and Google Sheets.
| Percentile | Common name | Meaning |
|---|---|---|
| 25th | First quartile (Q1) | 25% of values fall below this point |
| 50th | Median (Q2) | Half of values fall below this point |
| 75th | Third quartile (Q3) | 75% of values fall below this point |
| 90th | Top decile boundary | 90% of values fall below this point |
| 10th | Bottom decile boundary | 10% of values fall below this point |
| 99th | Top percentile range | 99% of values fall below this point |
Percentile explained simply
Percentile explained simply means showing where one value stands relative to the rest of a data set, expressed as a position out of 100. If a test score sits at the 80th percentile, that score is higher than 80 percent of all other scores in the comparison group. Percentiles are widely used in education, health growth charts, finance, and standardized testing to show relative ranking rather than a raw number.
The percentile formula
The percentile formula uses linear interpolation to find a value at any percentile, even when that percentile does not land exactly on one of the data points.
Here, p is the percentile you want to find and n is the total number of data points after sorting them in ascending order. If r is a whole number, the percentile equals the data value at that exact position. If r includes a decimal, the result is interpolated between the two closest sorted values using the fractional part of r.
Worked example of percentile
A worked example of percentile shows how the formula handles a real data set. Suppose the sorted data set is 40, 42, 47, 53, 54, 59, 65 and you want the 25th percentile.
The 25th percentile of this data set is 44.5, which falls between the second and third sorted values.
How to use this percentile calculator
How to use this percentile calculator only requires a list of numbers and the percentile you want to find. Paste or type your data into the data set field, enter the desired percentile, and select Calculate.
- Enter your numbers into the data set field, separated by commas, spaces, or new lines.
- Enter the percentile you want to find, such as 25, 50, or 90.
- Choose the number of decimal places for the result.
- Select Calculate to see the percentile value and the full interpolation steps.
- Select Clear to reset the calculator and try a different data set.
Percentile versus percentage and quartile
Percentile versus percentage and quartile is a common source of confusion because the three terms sound similar but measure different things. Percentage is simply a portion out of 100 applied to a single number. Percentile shows the relative rank of a value within a full data set. Quartile is a specific type of percentile that splits data into four equal sections at the 25th, 50th, and 75th percentiles.
- Percentage describes a fraction of one number, such as 20% of 50.
- Percentile describes a ranking position within a group of numbers.
- Quartile is shorthand for the 25th, 50th, and 75th percentiles specifically.
Real world uses for percentile
Real world uses for percentile appear across testing, healthcare, and finance. Standardized test results are reported in percentiles to show how one student compares to a national group, pediatric growth charts use percentiles to track a child’s height and weight against peers, and income or salary data is often summarized using percentile bands.
- Comparing standardized test scores against a national sample.
- Tracking child growth measurements against pediatric growth charts.
- Reporting income or salary distribution across a population.
- Analyzing website load times or response times against performance benchmarks.