# Generate a random integer in given range

Return an integer from min to max, both included.

Canonical: https://1loc.dev/random/generate-a-random-integer-in-given-range/
Version: 1.0.0
Runtime: JavaScript · Node.js 22 / modern browsers
Verification: Usage lines executed in Node.js 22 and headless Chromium; no external services
Updated: 2026-10-28

## Implementation

```javascript
function randomInteger(min, max) { return Math.floor(Math.random() * (max - min + 1)) + min; }
```

## Usage

```javascript
const rolls = Array.from({ length: 1000 }, () => randomInteger(1, 3));
rolls.every(n => [1, 2, 3].includes(n)); // → true
new Set(rolls).size; // → 3
```

Lines marked → were executed in Node.js 22 and in headless Chromium, and each result was compared with the value shown. Lines marked e.g. are illustrative.

## Limits

- min and max must be integers. Both ends are included.
- For security-sensitive numbers, such as verification codes, use crypto.getRandomValues with rejection sampling, as in Generate a random string from given characters.

The function does not validate its arguments. Add checks where it receives untrusted input.

## Source and license

Original: https://github.com/phuocng/1loc/blob/14b481cf60dff1620ab1bb99a43b1f68068cdd9b/contents/generate-a-random-integer-in-given-range.mdx
Author: Nguyen Huu Phuoc and original contributors
Contributors: See original repository history
Source commit: 14b481cf60dff1620ab1bb99a43b1f68068cdd9b
Copyright (c) 2020 phuoc-ng
License: MIT — https://1loc.dev/licenses/
Maintainer: Oveyon
Modifications: Documented as a reference with executed usage lines. Original MDX retained as inert source evidence.