Find Average of N Numbers in JavaScript

What You’ll Learn

The arithmetic mean of N numbers is their sum divided by N. This tutorial covers the formula, a live preview, algorithm steps, worked JavaScript examples, edge cases, and complexity.

📝 Problem & Approach

Given N positive count and N numeric values, compute their arithmetic mean.

// Example: 1, 2, 3, 4, 5
// Sum = 15, N = 5
// Average = 15 / 5 = 3.0

Inputs & Outputs

Minimal workflow

function averageOfN(n):
    if n <= 0:
        return error
    sum = 0
    repeat n times:
        read x
        sum = sum + x
    return sum / n

Method comparison

🔮 Live Preview

Enter comma-separated numbers and view count, sum, and average.

Press "Run" to see results.

Examples Gallery

Three complete JavaScript programs with Try it Yourself editors — input loop, array helper, and Array.reduce mean. Click View Output to reveal sample console results.

function averageOfNNumbers(n, values) {
  if (n <= 0) {
    return 0;
  }

  let total = 0;
  for (let i = 0; i < n; i++) {
    total += values[i];
  }

  return total / n;
}

const n = 5;
const values = [1, 2, 3, 4, 5];
const result = averageOfNNumbers(n, values);
console.log("The average of the entered numbers is: " + result.toFixed(6));

The average of the entered numbers is: 3.000000

function averageFromArray(values) {
  if (!values.length) {
    return 0;
  }
  let total = 0;
  for (let i = 0; i < values.length; i++) {
    total += values[i];
  }
  return total / values.length;
}

const data = [10, 15, 20, 25, 30];
const avg = averageFromArray(data);
console.log("Average = " + avg.toFixed(6));

Average = 20.000000

function mean(values) {
  if (!values.length) {
    return 0;
  }
  return values.reduce(function (sum, x) {
    return sum + x;
  }, 0) / values.length;
}

const data = [1, 2, 3, 4, 5];
console.log(mean(data));

3

🔎 Worked Walkthrough — 1, 2, 3, 4, 5

Trace a running-sum loop for five values. Start with total = 0.0 and N = 5.

Final mean: 15.0 / 5 = 3.0.

⚖️ Facts Worth Knowing

Handy follow-ups interviewers sometimes ask.

🎯 Practice Problems

Try these variations to lock in the pattern.

Notes

⏱️ Time and Space Complexity

💡 Best Practices