# Generate a random number or integer in a range with JavaScript

JavaScript's `Math.random()`

is handy for generating **random numbers between 0 and 1**. If you need a random number in a different range, you'll need to use some simple math to map the random number to the desired range.

## Random number in a range

The simplest use case you'll come across is to generate a **random number in a specified range**. All you need to do is multiply the result of `Math.random()`

by the **difference** between the maximum and minimum values, and then add the minimum value.

const randomNumberInRange = (min, max) => Math.random() * (max - min) + min; randomNumberInRange(2, 10); // 6.0211363285087005

## Random integer in a range

Subsequently, generating a **random integer** is very similar, except for an additional step at the end. You need to use `Math.floor()`

to **round the result down** to the nearest integer.

const randomIntegerInRange = (min, max) => Math.floor(Math.random() * (max - min + 1)) + min; randomIntegerInRange(0, 5); // 2

## Gaussian random numbers

Finally, if you need to generate Gaussian (**normally distributed**) random numbers, you can use the Box-Muller transform to generate random numbers with a Gaussian distribution.

const randomGauss = () => { const theta = 2 * Math.PI * Math.random(); const rho = Math.sqrt(-2 * Math.log(1 - Math.random())); return (rho * Math.cos(theta)) / 10.0 + 0.5; }; randomGauss(); // 0.5