Percentile Calculator

Percentiles describe where a value sits inside a distribution — the 90th percentile is the value below which 90% of the data falls. Enter a data set and the percentile you need, and this calculator returns the value using the same interpolation method as Excel’s PERCENTILE.INC.

Separate numbers with commas or spaces

Results

Formula

With the data sorted, the percentile sits at a fractional position:
Position = (p ÷ 100) × (n − 1)
If the position falls between two values, the result interpolates linearly between them.

How to use this calculator

  1. Enter your data set (any order — it is sorted automatically).
  2. Enter the percentile you want, from 0 to 100.
  3. Press Calculate for the interpolated value.
Percentile Calculator — how the calculation works, illustrated
Percentile Calculator — how the calculation works, illustrated

Worked example

Data: 15, 20, 35, 40, 50. Find the 75th percentile.

  1. Sorted data has 5 values, so position = 0.75 × 4 = 3 (0-based).
  2. The value at position 3 is 40.

Result: The 75th percentile is 40.

Frequently asked questions

Is the 50th percentile the same as the median?

Yes — with the interpolation method used here, the 50th percentile equals the median.

Why do different tools give slightly different percentile values?

Several definitions exist (nearest-rank, various interpolations). We use linear interpolation, matching Excel PERCENTILE.INC and NumPy’s default, and we say so on the page.

What does it mean to score in the 90th percentile?

Your score is at or above 90% of the comparison group — a rank statement, not “90% correct.”

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