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% Percentile Calculator

Find the percentile rank of any value in a data set, or determine what value falls at a given percentile. Also calculates Q1, Q2, Q3, and the full five-number summary.

Enter a comma-separated data set and a value to find what percentile that value falls in.

Percentile Formulas

Percentile Rank: PR = (values below x / n) × 100
Value at Percentile: L = (p / 100) × n → interpolate if needed
Quartiles: Q1 = 25th, Q2 = 50th (median), Q3 = 75th percentile

How Percentile Rank is Calculated

  1. 1
    Sort the Data
    Arrange all values in ascending order from smallest to largest.
  2. 2
    Count Values Below x
    Count how many data points are strictly less than the target value x.
  3. 3
    Apply the Formula
    Percentile Rank = (count below / total n) × 100. The result tells you what percentage of values fall below x.
  4. 4
    Identify Quartiles
    Q1, Q2, and Q3 are automatically derived using the same percentile method at the 25th, 50th, and 75th percentiles.

Worked Example

Data: 10, 20, 30, 40, 50, 60, 70, 80, 90, 100 — What percentile is 70?

Values below 70: 10, 20, 30, 40, 50, 60 → count = 6
PR = (6 / 10) × 100 = 60th percentile
Q1 = 25, Q2 = 55, Q3 = 75
Five-number summary: 10 | 25 | 55 | 75 | 100

Frequently Asked Questions

A percentile indicates the value below which a given percentage of observations fall. For example, if you score in the 80th percentile on a test, 80% of test-takers scored below you.

A percentage is a ratio out of 100 (e.g. you got 80% of answers right). A percentile is a ranking relative to others (e.g. you scored better than 80% of people). They measure different things.

Quartiles divide a sorted data set into four equal parts. Q1 (25th percentile) is the lower quartile, Q2 (50th) is the median, and Q3 (75th) is the upper quartile. The interquartile range (IQR = Q3 − Q1) measures spread.

Percentiles are used in standardized testing (SAT, GRE), pediatric growth charts, income distribution analysis, and any situation where relative rank matters more than absolute value.

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