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Percentile Calculator (Rank and Value)

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Percentile Calculator

This calculator works in both directions. In value mode you give it a data set and a percentile such as 90, and it returns the value that 90% of the data falls below. In rank mode you give it a data set and a score, and it tells you what percentage of the data lies below that score. Both modes show the sorted data and the position arithmetic.

Percentiles are defined by position in the sorted list, and there is more than one convention for a position that falls between two data points. The main answer uses linear interpolation, the same method as Excel’s PERCENTILE.INC and Python’s default, and the calculator also prints the exclusive and nearest-rank results so you can match whichever rule your course uses.

For percentile rank, ties are counted as half below (the “rank” convention in SciPy), with the strict and weak variants shown too. If you need a percentile from a mean and standard deviation rather than raw data, use the z-score calculator.

Separate values with commas, spaces or new lines.

Result and step-by-step solution

90th percentile
90.7

Linear interpolation (Excel PERCENTILE.INC, NumPy default). Exclusive method: 93.8. Nearest-rank method: 91.

  1. Sort the data (n = 12)
    55, 62, 67, 70, 71, 74, 78, 80, 84, 88, 91, 95
  2. Find the rank position
    position = 1 + (n − 1) × P/100 = 1 + 11 × 0.9 = 10.9
  3. Interpolate
    Position 10.9 lies between sorted values 88 (position 10) and 91 (position 11): 88 + 0.9 × (91 − 88) = 90.7.
  4. Nearest-rank check
    Rank = ⌈0.9 × 12⌉ = 11, giving 91. Textbooks differ on the method, so state which one you used.

Frequently asked questions

What does the 90th percentile mean?
The value below which 90% of the observations fall. If your score is at the 90th percentile you did better than about nine out of ten people.
How is the percentile rank of a score calculated?
Count the values below the score, add half the values equal to it, divide by the total number of values and multiply by 100.
Why does Excel give a different percentile?
PERCENTILE.INC uses linear interpolation on positions 1 + (n − 1)p, which is the main result here. PERCENTILE.EXC uses (n + 1)p and is shown as the exclusive value.
Is the 50th percentile the same as the median?
Yes, under every common convention the 50th percentile equals the median.

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Last reviewed: September 25, 2026. Calculations run in your browser and were validated against SciPy.

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