How to generate a n-digit number using JavaScript?
Last Updated :
12 Jul, 2025
The task is to generate an n-Digit random number with the help of JavaScript.
You can also generate random numbers in the given range using JavaScript.
Below are the approaches to generate a n-digit number using JavaScript:
Using Math.random()
Get the minimum and maximum number of n digits in variable min and max respectively. Then generate a random number using Math.random()(value lies between 0 and 1). Multiply the number by (max-min+1), get its floor value, and then add a min value to it.
Example: The example below shows how to generate a n-digit number using JavaScript.
HTML
<!DOCTYPE HTML>
<html>
<head>
<title>
Generate a n-digit
number using JavaScript
</title>
<style>
body {
text-align: center;
}
h1 {
color: green;
}
#geeks {
color: green;
font-size: 29px;
font-weight: bold;
}
</style>
</head>
<body>
<p>
<!-- min and max are 5 digit so-->
Click on the button to
generate random 5 digit
number
</p>
<button onclick="gfg();">
click here
</button>
<p id="geeks">
</p>
<script>
let up = document.getElementById('GFG_UP');
let down = document.getElementById('geeks');
function gfg() {
let minm = 10000;
let maxm = 99999;
down.innerHTML = Math.floor(Math
.random() * (maxm - minm + 1)) + minm;
}
</script>
</body>
</html>
Output:
OutputMath.random() Method and .substring() Method
Math.random() method use .substring() method to generate a random number between 0 and 1. Now we will use to get a part of the random number after converting it to string.
Example: The example shows How to generate a n-digit number using Math.random() Method and .substring() Method.
HTML
<!DOCTYPE HTML>
<html>
<head>
<title>
Generate a n-digit number using JavaScript
</title>
<style>
body {
text-align: center;
}
h1 {
color: green;
}
#geeks {
color: green;
font-size: 29px;
font-weight: bold;
}
</style>
</head>
<body style="text-align:center;">
<p>
Click on the button to generate
random 6 digit number
</p>
<button onclick="gfg();">
click here
</button>
<p id="geeks">
</p>
<script>
let down = document.getElementById('geeks');
function gfg() {
down.innerHTML = ("" + Math.random()).substring(2, 8);
}
</script>
</body>
</html>
Output:
Output
