JavaScript Program to Find the Largest of Three Numbers

Finding the largest of three numbers is a classic way to practice comparison operators and nested conditions. JavaScript also ships a built-in shortcut, Math.max(), which does the same job in one line — useful to know once you understand how the manual version works.

Program to Find the Largest of Three Numbers Using if...else

function largestOfThree(a, b, c) {
  if (a >= b && a >= c) {
    return a;
  } else if (b >= a && b >= c) {
    return b;
  } else {
    return c;
  }
}

console.log(largestOfThree(23, 89, 47));

Output:

89

Each branch uses >= (not just >) so that the function still returns a sensible value when two or more numbers are equal — for example, largestOfThree(5, 5, 3) correctly returns 5.

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Program Using Math.max()

const a = 23, b = 89, c = 47;

const largest = Math.max(a, b, c);

console.log("Largest number:", largest);

Output:

Largest number: 89

Math.max() accepts any number of arguments, so the same function also works for four, five, or more numbers — or, combined with the spread operator, for an entire array: Math.max(...numbersArray).

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