Percentile Calculator
Paste a data set to find the value at any percentile, or the percentile rank of one value inside it. Matches Excel's PERCENTILE.INC.
Your data set
Count
8
Median
4.5
Rank of 5
62.5%
Sorted: 2, 4, 4, 4, 5, 5, 7, 9
50th percentile
4.5
Position 3.5 of 7
What a percentile is
A percentile is a value with a given share of the data below it. If your exam score is at the 90th percentile, 90% of candidates scored lower.
Percentiles say nothing about the size of the gaps. Being at the 99th percentile tells you almost everyone is below you. It does not tell you whether you beat them narrowly or by a mile.
How this calculator works it out
- Sort the data from smallest to largest.
- Find the position: Percentile ÷ 100 × (Count − 1).
- If the position is a whole number, take that value. If it falls between two, interpolate between them.
Worked example — the 50th percentile of 2, 4, 4, 4, 5, 5, 7, 9
Count is 8, so positions run 0 to 7.
50 ÷ 100 × 7 = 3.5
Position 3 holds 4, position 4 holds 5.
Halfway between gives 4.5.
Percentile rank is the inverse
A percentile takes a percentage and gives back a value. A percentile rank takes a value and gives back a percentage. This calculator shows both, because people arrive wanting one or the other and the words are easy to confuse.
For the rank, ties count as half. A value equal to some data points sits halfway through them rather than above or below them all.
Why tools disagree
There are at least nine accepted ways to compute a percentile. They all agree when the position lands exactly on a data point, and differ when it lands between two.
This calculator uses linear interpolation, which is what Excel's PERCENTILE.INC and NumPy's percentile do by default. If a result here disagrees with another tool, the method is almost always the reason — not an error.
Quartiles are percentiles
- The first quartile is the 25th percentile.
- The second quartile, the median, is the 50th.
- The third quartile is the 75th.
Common questions
- What is a percentile?
- A percentile is the value below which a given share of a data set falls. The 90th percentile is the value that 90% of the data sits below.
- How is a percentile calculated?
- Sort the data, then find the position given by the percentile divided by 100 times one less than the count. If that position falls between two data points, interpolate between them. This matches Excel's PERCENTILE.INC and NumPy's default.
- What is the difference between a percentile and a percentile rank?
- A percentile takes a percentage and returns a value. A percentile rank takes a value and returns the percentage of the data below it. They are inverses of each other.
- Is the 50th percentile the same as the median?
- Yes. The 50th percentile is the median by definition — the value with half the data below it.
- Why do different tools give different percentiles?
- There are at least nine accepted methods. They differ in how they handle a position that falls between two data points. This calculator uses linear interpolation, the method Excel and NumPy use by default.