For AI agents: the complete documentation index is available at /llms.txt, the full documentation bundle is available at /llms-full.txt, and this page is available as Markdown at /reference/math/percentile.md.

percentile es-toolkit

Calculates the value at the given percentile of an array of numbers.

percentile sorts the array in ascending order and returns the element at the nearest rank (Nearest rank method).

const value = percentile(arr, p);

Usage

percentile(arr, percentile)

Use percentile when you want to find the value at a specific percentile of a numeric array. For example, the 50th percentile is the median, and the 75th percentile is the value below which 75% of the data falls.

import { percentile } from 'es-toolkit/math';

// Find the median (50th percentile) of an array
const median = percentile([1, 2, 3, 4, 5], 50); // median is 3

// Find the 75th percentile
const p75 = percentile([1, 2, 3, 4, 5], 75); // p75 is 4

// Unsorted arrays are automatically sorted
const result = percentile([50, 10, 30, 20, 40], 50); // result is 30

// The 0th percentile returns the smallest value
const min = percentile([5, 1, 4, 2, 3], 0); // min is 1

// Returns NaN for an empty array
const empty = percentile([], 50); // empty is NaN

Parameters

arrreadonly number[]required

An array of numbers to calculate the percentile from.

percentilenumberrequired

The percentile to compute, in the range [0, 100].

Returns

Returns the value at the given percentile. Returns NaN if the array is empty.

number

Throws

Throws an error if percentile is NaN, less than 0, or greater than 100.

Source: es-toolkit

Re-exported verbatim from es-toolkit. Implementation, edge cases, and performance behavior are owned upstream. This page mirrors the documentation at the pinned version; the linked source is authoritative.