How to Generate a Random Number in JavaScript ?

JavaScript allows us to generate random numbers using Math.random() method, which return a pseudo-random floating-point number between 0 (inclusive) and 1 (exclusive).

To obtain random integers within a specific range, one often uses a combination of Math.random(), multiplication, and rounding.

Using Math.random() method

The Math.random() method in JavaScript is a foundational function for generating pseudo-random floating-point numbers between 0 (inclusive) and 1 (exclusive).

Example: Randomly generating floating point number between 0 and 1 using the Math.round() method.

Javascript

function random()
{
    let randomNumber= Math.random();
      console.log(randomNumber)
}
random();

Output

0.576247647158219

Using Math.floor() with Math.random()

Using Math.floor() with Math.random() in JavaScript enables the creation of random integers within a defined range. This combination ensures a predictable outcome for applications such as games and simulations.”

Example: Randomly generating integer within a specific range using the Math.floor() method along with the Math.random() method.

Javascript

function random() {
  let randomNo = Math.floor(Math.random() * 10);
  console.log(randomNo);
}
random();

Output

3

Using Math.ceil() with Math.random()

The Math.ceil() method in JavaScript is used to round a number up to the nearest integer greater than or equal to the original value.

Example: Generating random integer using Math.ceil() along with math.random() method.

Javascript

const randomInteger = Math.ceil(Math.random() * 10);

console.log(randomInteger);

Output

10

Using Math.round() with Math.random()

Using Math.round() with Math.random() in JavaScript allows for the generation of random integers by rounding the result of Math.random(). This is commonly used when a fair rounding to the nearest integer is needed.

Example: The below code uses Math.round() with Math.random() to generate random number.

Javascript

const randomInteger = Math.round(Math.random() * 10);

console.log(randomInteger);

Output

4