JavaScript Program to Find the Largest Among Three Numbers

In this example, you will learn to find the largest among three numbers in JavaScript.

To understand this example, you should have the knowledge of the following JavaScript programming topics:


You can find the largest among three numbers using the if...else statement.

Example 1: Largest Number Among Three Numbers

// program to find the largest among three numbers

// take input from the user
let num1 = parseFloat(prompt("Enter first number: "));
let num2 = parseFloat(prompt("Enter second number: "));
let num3 = parseFloat(prompt("Enter third number: "));
let largest;

// check the condition
if(num1 >= num2 && num1 >= num3) {
    largest = num1;
}
else if (num2 >= num1 && num2 >= num3) {
    largest = num2;
}
else {
    largest = num3;
}

// display the result
console.log("The largest number is " + largest);

Output

Enter first number: -7
Enter second number: -5
Enter third number: -1
The largest number is -1

In the above program, parseFloat() is used to convert numeric string to number. If the string is a floating number, parseFloat() converts the string into floating point number.

The numbers are compared with one another using greater than or equal to >= operator. And the if...else if...else statement is used to check the condition.

Here, logical AND && is also used to check two conditions.


You can also use the JavaScript built-in Math.max() function to find the largest among the numbers.

Example2: Using Math.max()

// program to find the largest among three numbers

// take input from the user
let num1 = parseFloat(prompt("Enter first number: "));
let num2 = parseFloat(prompt("Enter second number: "));
let num3 = parseFloat(prompt("Enter third number: "));

let largest = Math.max(num1, num2, num3);

// display the result
console.log("The largest number is " + largest);

Output

Enter first number: 5
Enter second number: 5.5
Enter third number: 5.6
The largest number is 5.6

Math.max() returns the largest number among the provided numbers.


You can use Math.min() function to find the smallest among the numbers.